Ammonia-oxidizing bacteria

ABSTRACT

Described herein are novel ammonia-oxidizing bacteria as well as isolated nucleotide sequences representative of 16S rDNA of these ammonia-oxidizing bacteria. Particular bacteria of the present invention are tolerant of freshwater environments, saltwater environments or both. Furthermore, in various embodiments, various bacteria of the present invention are capable of surviving a freeze-drying process, and may remain viable thereafter. Compositions including various combinations of the bacteria are further described, as are polymerase chain reaction (PCR) primers and oligonucleotide probes that may be used to detect these bacteria based on their 16S rDNA.

This is a Continuation-in-Part of U.S. patent application Ser. No.09/573,684, filed May 19, 2000, now abandoned, which is incorporatedherein in its entirety. This application claims the benefit of priorityunder 35 U.S.C. § 119 of provisional U.S. application Ser. No.60/386,217, filed Sep. 19, 2002, provisional U.S. application Ser. No.60/386,218, filed Sep. 19, 2002 and provisional U.S. application Ser.No. 60/386,219, filed Sep. 19, 2002, the contents of all of which arehereby incorporated by reference.

FIELD OF THE INVENTION

The invention relates generally to ammonia oxidizers and specifically tobacteria capable of oxidizing ammonia to nitrite.

BACKGROUND OF THE INVENTION

Ammonia is the principal nitrogenous waste product of teleosts and manyinvertebrates in both freshwater and seawater. The ammonia results fromthe deamination or transamination of proteins the organism receives viaits diet. However, high ammonia concentrations can be toxic to many ofthese same aquatic organisms. In natural systems, such as lakes, riversand oceans, the concentration of ammonia rarely reaches deleteriouslevels because the density of fish (and other organisms) per mass ofwater is low.

However, in man-made aquatic systems such as aquaculture rearing pens,tanks, raceways and ponds plus aquaria, both public and private, ammoniacan reach toxic concentrations, sometimes very quickly. One reason forthis is that in the above-named systems the fish density can be verylarge in relation to the small amount of water. Another reason is thatin many of these systems the water is not continually changed; rather itrecirculates through the system with only periodic partial waterchanges.

Therefore, most aquaculture systems and aquaria use filtration, in oneform or another, to maintain a degree of water quality that is suitablefor the maintenance and growth of aquatic organisms. A major componentof any such filtration unit is the biological filter. The biologicalfilter gets its name from the fact that it acts as a substrate or sitefor the growth of bacteria which have the capability to convert, by wayof oxidation, ammonia to another compound—nitrite. High concentrationsof nitrite can also be toxic but there are other species of bacteriawhich grow on the biological filter and oxidize the nitrite to nitrate,such as those described in U.S. Pat. Nos. 6,268,154, 6,265,206 and6,207,440, each of which is incorporated by reference herein in itsentirety as if fully set forth. Nitrate is considered non-toxic toaquatic organisms except in extreme cases of very high concentrations.

There are other situations or applications which use biological filters.These include sewage treatment facilities, wastewater treatmentfacilities and drinking water filtration plants. While each will haveits own particular reason for using a biological filter, the goal is thesame: the conversion of toxic inorganic nitrogen compounds to lessharmful inorganic nitrogen substances. Biological filtration isnecessary for many facilities to meet the National Recommended WaterQuality Criteria as set by the Environmental Protection Agency (EPA) ofthe United States of America.

The oxidation of ammonia to nitrite is a bacterially-mediated process.Specifically, it is a two step oxidation process involving theconversion of ammonia to nitrite according to the following equations:NH₃+O₂+H₂O+2e ⁻--->NH₂OH+H₂O  (1)NH₂OH+H₂O--->NO₂ ⁻+5H⁺+4e ⁻  (2)

The most commonly studied ammonia oxidizing bacteria (AOB) isNitrosomonas europaea. It was originally isolated from soils and ispurported to be the active AOB in aquaculture facilities (Wheaton, F. W.1977. Aquacultural Engineering. John Wiley & Sons, Inc. New York.), inwastewater treatment facilities (Painter, H. A. 1986. Nitrification inthe treatment of sewage and waste-waters. In Nitrification J. I. Prossered. IRL Press. Oxford.) and in aquaria (Spotte, S. 1979. SeawaterAquariums—The Captive Environment. Wiley-Interscience. New York). Thesereferences, and all other references cited herein are herebyincorporated by reference in their entirety as if fully set forth.

However, recent research conducted with modem molecular methods whichuse the uniqueness of the DNA sequence of an organism (or group oforganisms) has shown that N. europaea and its close relatives were belowdetection limits in freshwater aquaria environments (Hovanec, T. A. andE. F. DeLong. 1996. Comparative analysis of nitrifying bacteriaassociated with freshwater and marine aquaria. Appl. Environ. Microbiol.62:2888-2896.). Other research has demonstrated that N. europaea is notthe dominant AOB in wastewater treatment facilities (Juretschko, S. et.al. 1998. Combined molecular and conventional analyses of nitrifyingbacterium diversity in activated sludge: Nitrosococcus mobilis andNitrospira-like bacteria as dominant populations. Appl. Environ.Microbiol. 64:3042-3051).

Moreover, an environmental factor of particular import with aquariaenvironments and wastewater treatment is salinity, and, morespecifically, the numerous physicochemical differences betweenfreshwater and saltwater environments. The distinction among variousAOBs in their ability to tolerate such dramatic changes in localenvironment is critical in the design of these systems andimplementation of AOBs therein. As such, a demonstrated tolerance by aparticular AOB to a saltwater environment may render that AOB suitablefor use in particular aquaria and wastewater environments, and,moreover, a resilience to withstand the change between a freshwater andsaltwater environment may have even broader implications.

Furthermore, the storage and transport of AOB is often limited to liquidand similar, potentially inconvenient media, owing, at least in part, tothe inability of various strains of AOB to withstand a freeze-dryingprocess. Such a process allows one to formulate a volume of AOB into asolid, freeze-dried powder or similar composition that may be tolerantof greater fluctuations in, e.g., temperature, and may becorrespondingly more practical for purposes of shipping and handling ina commercialized product, or similar considerations, and for maintainingan extended shelf-life.

Thus, there exists a need in the art for the identification of AOBs,particularly those which are capable of tolerating a saltwaterenvironment and/or both saltwater and freshwater environments. There isalso a need in the art for AOBs that remain viable after being subjectedto a freeze-drying process.

SUMMARY OF THE INVENTION

In an embodiment of the present invention, isolated bacteria orbacterial strains capable of oxidizing ammonia to nitrite are provided.In one embodiment, the 16S rDNA of the bacteria or bacterial strainshave the nucleotide sequence of SEQ ID NO:1, SEQ ID NO:2, SEQ ID NO:3,SEQ ID NO:4, SEQ ID NO:18, SEQ ID NO:19 or SEQ ID NO:20. The nucleotidesequences described as SEQ ID NO:18, SEQ ID NO:19 and SEQ ID NO:20 areexemplary of Nitrosomonas aestuarii-like AOB. The Nitrosospira-like AOBrepresented by SEQ ID NO:1, SEQ ID NO:2 and SEQ ID NO:3 have beendeposited with the American Type Culture Collection (ATCC) and have beenassigned accession numbers PTA-1888, PTA-1887 and PTA-1885,respectively. The Nitrosomonas-like AOB represented by SEQ ID NO:4 hasbeen deposited with the ATCC and has been assigned accession numberPTA-1886. The Nitrosomonas aestuarii-like AOB represented by SEQ IDNO:18, SEQ ID NO:19 and SEQ ID NO:20 have been deposited with the ATCCand have been assigned accession number PTA-5423.

In various embodiments, the 16S rDNA of the bacteria or bacterialstrains have the nucleotide sequence of SEQ ID NO:18, SEQ ID NO:19 orSEQ ID NO:20 (i.e., the Nitrosomonas aestuarii-like AOB), SEQ ID NO:1,SEQ ID NO:2, SEQ ID NO:3, SEQ ID NO:4 or a variant thereof which is atleast 96% similar, at least 97% similar, at least 98% similar or atleast 99% similar to SEQ ID NO:1, SEQ ID NO:2, SEQ ID NO:3, SEQ ID NO:4,SEQ ID NO:18, SEQ ID NO:19 or SEQ ID NO:20.

The present invention also includes nucleic acid sequences and bacteriawith sequences which have the nucleotide sequence of SEQ ID NO:1, SEQ IDNO:2, SEQ ID NO:3, SEQ ID NO:4, SEQ ID NO:18, SEQ ID NO:19 or SEQ IDNO:20 or a variant thereof which is at least 96% similar, at least 97%similar, at least 98% similar or at least 99% similar to SEQ ID NO:1,SEQ ID NO:2, SEQ ID NO:3, SEQ ID NO:4, SEQ ID NO:18, SEQ ID NO:19 or SEQID NO:20.

For the purposes of this application, “96% similar” means that singlebase substitutions may occur in up to 4% of the bases, “97% similar”means that single base substitutions may occur in up to 3% of the bases,“98% similar” means that single base substitutions may occur in up to 2%of the bases and “99% similar” means that single base substitutions mayoccur in up to 1% of the bases.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates the phylogenetic relationships of three bacterialstrains (i.e., those represented by SEQ ID NO:1, SEQ ID NO:2 and SEQ IDNO:3) and one substrain (i.e., that strain represented by SEQ ID NO:4)inferred from comparative analysis of 16S rDNA sequences in accordancewith an embodiment of the present invention. The tree is based onneighbor-joining distance analysis of sequences containing a minimum of1430 nucleotides.

FIG. 2 illustrates a denaturing gradient gel electrophoresis (DGGE) ofbiomasses from selected cultures and ammonia-oxidizing bacteriarepresented by SEQ ID NO:1, SEQ ID NO:2, SEQ ID NO:3 and SEQ ID NO:4, inaccordance with an embodiment of the present invention.

FIG. 3 illustrates a DGGE demonstrating the uniqueness of the bacterialstrains represented by SEQ ID NO:1, SEQ ID NO:2, SEQ ID NO:3 and SEQ IDNO:4, in accordance with an embodiment of the present invention. Thereare two replicates of each aforementioned bacterial type along withextracts from three pure cultures of ammonia-oxidizing bacteria.

FIG. 4 (A-D′) illustrates mean ammonia and nitrite trends for theBacterial Additives VI test for the bacterial strains represented by SEQID NO:1, SEQ ID NO:2, SEQ ID NO:3 and SEQ ID NO:4, in accordance with anembodiment of the present invention.

FIG. 5 (A-D′) illustrates mean ammonia and nitrite trends for theBacterial Additives VII test for the bacterial strains represented bySEQ ID NO:1, SEQ ID NO:2, SEQ ID NO:3 and SEQ ID NO:4, in accordancewith an embodiment of the present invention.

FIG. 6 illustrates the phylogenetic relationships of two bacterialstrains (i.e., those represented by SEQ ID NO:18 and SEQ ID NO:19), andone substrain (i.e., that represented by SEQ ID NO:20) inferred fromcomparative analysis of 16S rDNA sequences in accordance with anembodiment of the present invention. The tree further depicts therelationship among the two bacterial strains represented by SEQ ID NO:18and SEQ ID NO:19 and the bacterial strains represented by SEQ ID NO:1,SEQ ID NO:2, SEQ ID NO:3 and SEQ ID NO:4. The tree is based onneighbor-joining distance analysis of sequences containing a minimum of1430 nucleotides.

FIG. 7 illustrates a denaturing gradient gel electrophoresis (DGGE) ofthe biomasses from selected freshwater cultures of ammonia-oxidizingbacteria represented by SEQ ID NO:1, SEQ ID NO:3 and SEQ ID NO:4 alongwith seawater cultures of ammonia-oxidizing bacteria represented by SEQID NO:18, SEQ ID NO:19 and SEQ ID NO:20 and pure cultures of theammonia-oxidizing bacteria Nitrosomonas europaea, Nitrosomonasmultiformis, and Nitrosomonas cryotolerans.

FIG. 8 illustrates mean ammonia concentration trends for the BacterialAdditives VIII test for freshwater bacterial strains represented by SEQID NO:1, SEQ ID NO:2, and SEQ ID NO:3 and seawater bacterial strainsrepresented by SEQ ID NO:18, SEQ ID NO:19 and two N. halophila-likestrains in accordance with an embodiment of the present invention alongwith two commercially available nitrifying bacteria mixtures.

FIG. 9 illustrates mean ammonia concentration trends for aquaria in theBacterial Additives IX test that were dosed with seawater bacterialstrains represented by SEQ ID NO:18, SEQ ID NO:19 and two N.halophila-like strains in accordance with an embodiment of the presentinvention.

FIG. 10 illustrates mean ammonia concentration trends for the BacterialAdditives X test. Two bacterial mixtures of seawater bacterial strainsrepresented by SEQ ID NO:18, SEQ ID NO:19 and two N. halophila-likestrains were tested against non-inoculated aquaria in accordance with anembodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is based upon the discovery of novel bacterialstrains which are capable of ammonia oxidation in freshwater and/orsaltwater environments, and which can also survive and remain viablefollowing a freeze-drying process.

The present invention provides an isolated bacterial strain or abiologically pure culture of a bacterial strain capable of oxidizingammonia to nitrite, wherein the 16S rDNA of the bacterial strainincludes the nucleotide sequence of SEQ ID NO:1, SEQ ID NO:2, SEQ IDNO:3 and SEQ ID NO:4, SEQ ID NO:18, SEQ ID NO:19 or SEQ ID NO: 22 asshown in Tables 1 through 7.

TABLE 1 The sequence for the AOB Type A ammonia-oxidizing bacterium.Represented by R7clone140. SEQ ID NO: 1.ATTGAACGCTGGCGGCATGCTTTACACATGCAAGTCGAACGGCAGCACGGATGCTTGCATCTGGTGGCGAGTGGCGGACGGGTGAGTAATGCATCGGAACGTATCCAGAAGAGGGGGGTAACGCATCGAAAGATGTGCTAATACCGCATATACTCTAAGGAGGAAAGCAGGGGATCGAAAGACCTTGCGCTTTTGGAGCGGCCGATGTCTGATTAGCTAGTTGGTGGGGTAAAGGCCTACCAAGGCGACGATCAGTAGTTGGTCTGAGAGGACGACCAGCCACACTGGGACTGAGACACGGCCCAGACTCCTACGGGAGGCAGCAGTGGGGAATTTTGGACAATGGGCGCAAGCCTGATCCAGCAATGCCGCGTGAGTGAAGAAGGCCTTCGGGTTGTAAAGCTCTTTCAGTCGAGAAGAAAAGGTTACGGTAAATAATCGTGACTCATGACGGTATCGACAGAAGAAGCACCGGCTAACTACGTGCCAGCAGCCGCGGTAATACGTAGGGTGCAAGCGTTAATCGGAATTACTGGGCGTAAAGGGTGCGCAGGCGGCTTTGTAAGTCAGATGTGAAATCCCCGGGCTTAACCTGGGAATTGCGTTTGAAACTACAAGGCTAGAGTGTGGCAGAGGGAGGTGGAATTCCATGTGTAGCAGTGAAATGCGTAGAGATATGGAAGAACATCGATGGCGAAGGCAGCCTCCTGGGTTAACACTGACGCTCATGCACGAAAGCGTGGGGAGCAAACAGGATTAGATACCCTGGTAGTCCACGCCCTAAACGATGTCAACTAGTTGTTGGGCCTTATTAGGCTTGGTAACGAAGCTAACGCGTGAAGTTGACCGCCTGGGGAGTACGGTCGCAAGATTAAAACTCAAAGGAATTGACGGGGACCCGCACAAGCGGTGGATTATGTGGATTAATTCGATGCAACGCGAAAAACCTTACCTACCCTTGACATGTAGCGAATTTTCTAGAGATAGATTAGTGCTTCGGGAACGCTAACACAGGTGCTGCATGGCTGTCGTCAGCTCGTGTCGTGAGATGTTGGGTTAAGTCCCGCAACGAGCGCAACCCTTGTCATTAATTGCCATCATTTGGTTGGGCACTTTAATGAGACTGCCGGTGACAAACCGGAGGAAGGTGGGGATGACGTCAAGTCCTCATGGCCCTTATGGGTAGGGCTTCACACGTAATACAATGGCGCGTACAGAGGGTTGCCAACCCGCGAGGGGGAGCTAATCTCAGAAAGCGCGTCGTAGTCCGGATCGGAGTCTGCAACTCGACTCCGTGAAGTCGGAATCGCTAGTAATCGCGGATCAGCATGTCGCGGTGAATACGTTCCCGGGTCTTGTACACACCGCCCGTCACACCATGGGAGTGGGTTTCACCAGAAGCAGGTAGTCTAACCGTAAGGAGGGCGCTTGCCACGGTGAGATTCATGAC TGGGGTG

TABLE 2 The sequence f r the AOB Type A1 ammonia-oxidizing bacterium.Represented by R7clone187. SEQ ID NO: 2.ATTGAACGCTGGCGGCATGCTTTACACATGCAAGTCGAACGGCAGCACGGATGCTTGCATCTGGTGGCGAGTGGCGGACGGGTGAGTAATGCATCGGAACGTATCCAGAAGAGGGGGGTAACGCATCGAAAGATGTGCTAATACCGCATATACTCTAAGGAGGAAAGCAGGGGATCGAAAGACCTTGCGCTTTTGGAGCGGCCGATGTCTGATTAGCTAGTTGGTGGGGTAAAGGCCTACCAAGGCGACGATCAGTAGTTGGTCTGAGAGGACGACCAGCCACACTGGGACTGAGACACGGCCCAGACTCCTACGGGAGGCAGCAGTGGGGAATTTTGGACAATGGGCGCAAGCCTGATCCAGCAATGCCGCGTGAGTGAAGAAGGCCTTCGGGTTGTAAAGCTCTTTCAGTCGAGAAGAAAAGGTTACGGTAAATAATCGTGACCCATGACGGTATCGACAGAAGAAGCACCGGCTAACTACGTGCCAGCAGCCGCGGTAATACGTAGGGTGCAAGCGTTAATCGGAATTACTGGGCGTAAAGGGTGCGCAGGCGGCCTTGTAAGTCAGATGTGAAATCCCCGGGCTTAACCTGGGAATTGCGTTTGAAACTACAAAGCTAGAGTGTGGCAGAGGGAGGTGGAATTCCATGTGTAGCAGTGAAATGCGTAGAGATATGGAAGAACATCGATGGCGAAGGCAGCCTCCTGGGTTAACACTGACGCTCATGCACGAAAGCGTGGGGAGCAAACAGGATTAGATACCCTGGTAGTCCACGCCCTAAACGATGTCAACTAGTTGTTGGGCCTTATTAGGCTTGGTAACGAAGCTAACGCGTGAAGTTGACCGCCTGGGGAGTACGGTCGCAAGATTAAAACTCAAAGGAATTGACGGGGACCCGCACAAGCGGTGGATTATGTGGATTAATTCGATGCAACGCGAAAAACCTTACCTACCCTTGACATGTAGCGAATTTTCTAGAGATAGATTAGTGCTTCGGGAACGCTAACACAGGTGCTGCATGGCTGTCGTCAGCTCGTGTCGTGAGATGTTGGGTTAAGTCCCGCAACGAGCGCAACCCTTGTCATTAATTGCCATCATTTGGTTGGGCACTTTAATGAGACTGCCGGTGACAAACCGGAGGAAGGTGGGGATGACGTCAAGTCCTCATGGCCCTTATGGGTAGGGCTTCACACGTAATACAATGGCGCGTACAGAGGGTTGCCAACCCGCGAGGGGGAGCTAATCTCAGAAAGCGCGTCGTAGTCCGGATCGGAGTCTGCAACTCGACTCCGTGAAGTCGGAATCGCTAGTAATCGCGGATCAGCATGTCGCGGTGAATACGTTCCCGGGTCTTGTACACACCGCCCGTCACACCATGGGAGTGGGTTTCACCAGAAGCAGGTAGTCTAACCGTAAGGAGGGCGCTTGCCACGGTGAGATTCATGAC TGGGGTG

TABLE 3 The sequence for the AOB Type B ammonia-oxidizing bacterium.Represented by R3clone5. SEQ ID NO:3.ATTGAACGCTGGCGGCATGCTTTACACATGCAAGTCGAACGGCAGCACGGGGGCAACCCTGGTGGCGAGTGGCGAACGGGTGAGTAATACATCGGAACGTATCTTCGAGGGGGGGATAACGCACCGAAAGGTGTGCTAATACCGCATAATCTCCACGGAGAAAAGCAGGGGATCGCAAGACCTTGCGCTCTTGGAGCGGCCGATGTCTGATTAGCTAGTTGGTGAGGTAATGGCTTACCAAGGCGACGATCAGTAGCTGGTCTGAGAGGACGACCAGCCACACTGGGACTGAGACACGGCCCAGACTCCTACGGGAGGCAGCAGTGGGGAATTTTGGACAATGGGGGAAACCCTGATCCAGCCATGCCGCGTGAGTGAAGAAGGCCTTCGGGTTGTAAAGCTCTTTCAGCCGGAACGAAACGGTCACGGCTAATACCCGTGACTACTGACGGTACCGGAAGAAGAAGCACCGGCTAACTACGTGCCAGCAGCCGCGGTAATACGTAGGGTGCAAGCGTTAATCGGAATTACTGGGCGTAAAGCGTGCGCAGGCGGTTTTGTAAGTCAGATGTGAAAGCCCCGGGCTTAACCTGGGAACTGCGTTTGAAACTACAAGGCTAGAGTGTGGCAGAGGGGGGTGGAATTCCACGTGTAGCAGTGAAATGCGTAGAGATGTGGAGGAACACCGATGGCGAAGGCAGCCCCCTGGGTTAACACCGACGCTCAGGCACGAAAGCGTGGGGAGCAAACAGGATTAGATACCCTGGTAGTCCACGCCCTAAACGATGTCAACTAGTTGTCGGGTCTTAACGGACTTGGTAACGCAGCTAACGCGTGAAGTTGGCCGCCTGGGGAGTACGGTCGCAAGATTAAAACTCAAAGGAATTGACGGGGACCCGCACAAGCGGTGGATTATGTGGATTAATTCGATGCAACGCGAAAAACCTTACCTACCCTTGACATGTACCGAAGCCCGCCGAGAGGTGGGTGTGCCCGAAAGGGAGCGGTAACACAGGTGCTGCATGGCTGTCGTCAGCTCGTGTCGTGAGATGTTGGGTTAAGTCCCGCAACGAGCGCAACCCTTGTCATTAATTGCCATCATTCAGTTGGGCACTTTAATGAAACTGCCGGTGACAAACCGGAGGAAGGTGGGGATGACGTCAAGTCCTCATGGCCCTTATGGGTAGGGCTTCACACGTAATACAATGGCGCGTACAGAGGGTTGCCAACCCGCGAGGGGGAGCTAATCTCAGAAAGCGCGTCGTAGTCCGGATCGGAGTCTGCAACTCGACTCCGTGAAGTCGGAATCGCTAGTAATCGCGGATCAGCATGTCGCGGTGAATACGTTCCCGGGTCTTGTACACACCGCCCGTCACACCATGGGAGTGGGTTTCACCAGAAGCAGGTAGTCTAACCGCAAGGAGGGCGCTTGCCACGGTGAGATTCATGACTGGG GTG

TABLE 4 The sequence for the AOB Type C ammonia-oxidizing bacterium.Represented by R5clone47. SEQ ID NO: 4.ATTGAACGCTGGCGGCATGCTTTACACATGCAAGTCGAACGGCAGCGGGGGCTTCGGCCTGCCGGCGAGTGGCGAACGGGTGAGTAATACATCGGAACGTGTCCTTAAGTGGGGAATAACGCATCGAAAGATGTGCTAATACCGCATATCTCTGAGGAGAAAAGCAGGGGATCGCAAGACCTTGCGCTAAAGGAGCGGCCGATGTCTGATTAGCTAGTTGGTGGGGTAAAGGCTTACCAAGGCAACGATCAGTAGTTGGTCTGAGAGGACGACCAACCACACTGGGACTGAGACACGGCCCAGACTCCTACGGGAGGCAGCAGTGGGGAATTTTGGACAATGGGCGAAAGCCTGATCCAGCCATGCCGCGTGAGTGAAGAAGGCCTTCGGGTTGTAGAGCTCTTTTAGTCAGAAAGAAAGAATCATGATGAATAATTATGATTTATGACGGTACTGACAGAAAAAGCACCGGCTAACTACGTGCCAGCAGCCGCGGTAATACGTAGGGTGCGAGCGTTAATCGGAATTACTGGGCGTAAAGGGTGCGCAGGCGGTTTTGTAAGTCAGATGTGAAAGCCCCGGGCTTAACCTGGGAATTGCGTTTGAAACTACAAGGCTAGAGTGCAGCAGAGGGGAGTGGAATTCCATGTGTAGCAGTGAAATGCGTAGAGATGTGGAAGAACACCGATGGCGAAGGCAGCTCCCTGGGTTGACACTGACGCTCATGCACGAAAGCGTGGGGAGCAAACAGGATTAGATACCCTGGTAGTCCACGCCCTAAACGATGTCAACTGGTTGTCGGATCTAATTAAGGATTTGGTAACGTAGCTAACGCGTGAAGTTGACCGCCTGGGGAGTACGGTCGCAAGATTAAAACTCAAAGGAATTGACGGGGACCCGCACAAGCGGTGGATTATGTGGATTAATTCGATGCAACGCGAAAAACCTTACCTACCCTTGACATGCTTGGAATCTAGTGGAGACATAAGAGTGCCCGAAAGGGAGCCAAGACACAGGTGCTGCATGGCTGTCGTCAGCTCGTGTCGTGAGATGTTGGGTTAAGTCCCGCAACGAGCGCAACCCTTGTCACTAATTGCTATCATTCTAAATGAGCACTTTAGTGAGACTGCCGGTGACAAACCGGAGGAAGGTGGGGATGACGTCAAGTCCTCATGGCCCTTATGGGTAGGGCTTCACACGTAATACAATGGCGTGTACAGAGGGTTGCCAACCCGCGAGGGGGAGCCAATCTCAGAAAGCACGTCGTAGTCCGGATCGGAGTCTGCAACTCGACTCCGTGAAGTCGGAATCGCTAGTAATCGCGGATCAGCATGCCGCGGTGAATACGTTCCCGGGTCTTGTACACACCGCCCGTCACACCATGGGAGTGGTTTTCACCAGAAGCAGGTAGTTTAACCGTAAGGAGGACGCTTGCCACGGTGGGGGTCAT GACTGGGGTG

TABLE 5 The sequence for Nitrosomonas aestuarii-like AOB represented byP4clone42. SEQ ID NO: 18.TTGATCATGGCTCAGATTGAACGCTGGCGGCATGCTTTACACATGCAAGTCGAACGGCAGCACGGGTGCTTGCACCTGGTGGCGAGTGGCGGACGGGTGAGTAATGCATCGGAACGTGTCCAGAAGTGGGGGATAACGCATCGAAAGATGTGCTAATACCGCATATTCTCTACGGAGGAAAGCAGGGGATCGAAAGACCTTGTGCTTTTGGAGCGGCCGATGCCTGATTAGCTAGTTGGTGGGGTAAAGGCCTACCAAGGCAACGATCAGTAGTTGGTCTGAGAGGACGACCAGCCACACTGGGACTGAGACACGGCCCAGACTCCTACGGGAGGCAGCAGTGGGGAATTTTGGACAATGGGCGAAAGCCTGATCCAGCAATGCCGCGTGAGTGAAGAAGGCTTCGGGTTGTAAAGCTCTTTCAGTCGAGAAGAAAAGGTTGTGACTAATAATCACAACTTATGATGGTACCGACAGAAGAAGCACCGGCTAACTACGTGCCAGCAGCCGCGGTAATACGTAGGGTGCAAGCGTTAATCGGAATTACTGGGCGTAAAGGGTGCGCAGGCGGCTTTGTAAGTCAGATGTGAAATCCCCGGGCTTAACCTGGGAATTGCGTTTGAAACTACAAAGCTAGAGTGTAGCAGAGGGGGGTGGAATTCCATGTGTAGCAGTGAAATGCGTAGAGATATGGAAGAACATCGATGGCGAAGGCAGCCCCCTGGGTTAACACTGACGCTCATGCACGAAAGCGTGGGGAGCAAACAGGATTAGATACCCTGGTAGTCCACGCCCTAAACGATGTCAACTAGTTGTTGGGCCTTACTAGGCTTGGTAACGTAGCTAACGCGTGAAGTTGACCGCCTGGGGAGTACGGTCGCAGGATTAAAACTCAAAGGAATTGACGGGGACCCGCACAAGCGGTGGATTATGTGGATTAATTCGATGCAACGCGAAAAACCTTACCTACCCTTGACATGTAGCGAATATTTTAGAGATAAATAGTGCCTTCGGGAACGCTAACACAGGTGCTGCATGGCTGTCGTCAGCTCGTGTCGTGAGATGTTGGGTTAAGTCCCGCAACGAGCGCAACCCTTGTCATTAATTGCCATCATTTAGTTGGGCACTTTAATGAGACTGCCGGTGACAAACCGGAGGAAGGTGGGGATGACGTCAAGTCCTCATGGCCCTTATGGGTAGGGCTTCACACGTAATACAATGGCGCGTACAGAGGGTTGCCAACCCGCGAGGGGGAGCTAATCTCAGAAAGCGCGTCGTAGTCCGGATCGGAGTCTGCAACTCGACTCCGTGAAGTCGGAATCGCTAGTAATCGCGGATCAGCATGTCGCGGTGAATACGTTCCCGGGTCTTGTACACACCGCCCGTCACACCATGGGAGTGGGTTTCACCAGAAGCAGATAGTCTAACCGTAAGAGGGCGTTTGCCACGG CGAGATTCATGACTGG

TABLE 6 The sequence for Nitrosomonas aestuarii-like AOB represented byP4clone31. SEQ ID NO: 19.AGTTTGATCATGGCTCAGATTGAACGCTGGCGGCATGCTTTACACATGCAAGTCGAACGGCAGCACGGGTGCTTGCACCTGGTGGCGAGTGGCGGACGGGTGAGTAATGCATCGGAACGTGTCCGGAAGTGGGGGATAACGCATCGAAAGATGTGCTAATACCGCATATTCTCTACGGAGGAAAGCAGGGGATCGAAAGACCTTGTGCTTTTGGAGCGGCCGATGCCTGATTAGCTAGTTGGTGGGGTAAAGGCCTACCAAGGCAACGATCAGTAGTTGGTCTGAGAGGACGACCAGCCACACTGGGACTGAGACACGGCCCAGACTCCTACGGGAGGCAGCAGTGGGGAATTTTGGACAACGGGCGAAAGCCTGATCCAGCAATGCCGCGTGAGTGAAGAAGGCCTTCGGGTTGTAAAGCTCTTTCAGTCGAGAAGAAAAGGTTGTGACTAATAATCACAACTTATGACGGTACCGACAGAAGAAGCACCGGCTAACTACGTGCCAGCAGCCGCGGTAATACGTAGGGTGCAAGCGTTAATCGGAATTACTGGGCGTAAAGGGTGCGCAGGCGGCTTTGTAAGTCAGATGTGAAATCCCCGGGCTTAACCTGGGAATTGCGTTTGAAACTACAAAGCTAGAGTGTAGCAGAGGGGGGTGGAATTCCATGTGTAGCAGTGAAATGCGTAGAGATATGGAAGAACATCGATGGCGAAGGCAGCCCCCTGGGTTAACACTGACGCTCATGCACGAAAGCGTGGGGAGCAAACAGGATTAGATACCCTGGTAGTCCACGCCCTAAACGATGTCAACTAGTTGTTGGGCCTTACTAGGCTTGGTAACGTAGCTAACGCGTGAAGTTGACCGCCTGGGGAGTACGGTCGCAAGATTAAAACTCAAAGGAATTGACGGGGACCCGCACAAGCGGTGGATTATGTGGATTAATTCGATGCAACGCGAAAAACCTTACCTACCCTTGACATGTAGCGAATATTTTAGAGATAAAATAGTGCCTTCGGGAACGCTAACACAGGTGCTGCATGGCTGTCGTCAGCTCGTGTCGTGAGATGTTGGGTTAAGTCCCGCAACGAGCGCAACCCTTGTCATTAATTGCCATCATTTAGTTGGGCACTTTAATGAGACTGCCGGTGACAAACCGGAGGAAGGTGGGGATGACGTCAAGTCCTCATGGCCCTTATGGGTAGGGCTTCACACGTAATACAATGGCGCGTACAGAGGGTTGCCAACCCGCGAGGGGGAGCTAATCTCAGAAAGCGCGTCGTAGTCCGGATCGGAGTTAGCAACTCGACTCCGTGAAGTCGGAATCGCTAGTAATCGCGGATCAGCATGTCGCGGTGAATACGTTCCCGGGCCTTGTACACACCGCCCGTCACACCATGGAAGTTGGCTGCACCAGAAGTAGGTTGTCTAACCCTCGGGAGGACGCTTACCACGGTGTGGTCAATGACTTGGGGTGAAGTCGTAACAAGGTAA

TABLE 7 The sequence for Nitrosomonas aestuarii-like AOB represented byBF16clone57. SEQ ID NO: 20.GTTTGATCATGGCTCAGATTGAACGCTGGCGGCATGCTTTACACATGCAAGTCGAACGGCAGCACGGGTGCTTGCACCTGGTGGCGAGTGGCGGACGGGTGAGTAATGCATCGGAACGTGTCCAGAAGTGGGGGATAACGCATCGAAAGATGTGCTAATACCGCATATTCTCTACGGAGGAAAGCAGGGGATCGAAAGACCTTGTGCTTTTGGAGCGGCCGATGCCTGATTAGCTAGTTGGTGGGGTAAAGGCCTACCAAGGCAACGATCAGTAGTTGGTCTGAGAGGACGACCAGCCACACTGGGACTGAGACACGGCCCAGACTCCTACGGGAGGCAGCAGTGGGGAATTTTGGACAATGGGCGAAAGCCTGATCCAGCAATGCCGCGTGAGTGAAGAAGGCCTTCGGGTTGTAAAGCTCTTTCAGTCGAGAAGAAAAGGTTGTGACTAATAATCACAACTTATGACGGTACCGACAGAAGAAGCACCGGCTAACTACGTGCCAGCAGCCGCGGTAATACGTAGGGTGCAAGCGTTAATCGGAATTACTGGGCGTAAAGGGTGCGCAGGCGGCTTTGTAAGTCAGATGTGAAATCCCCGGGCTTAACCTGGGAATTGCGTTTGAAACTACAAAGCTAGAGTGTAGCAGAGGGGGGTGGAATTCCATGTGTAGCAGTGAAATGCGTAGAGATATGGAAGAACATCGATGGCGAAGGCAGCCCCCTGGGTTAACACTGACGCTCATGCACGAAAGCGTGGGGAGCAAACAGGATTAGATACCCTGGTAGTCCACGCCCTAAACGATGTCAACTAGTTGTTGGGCCTTACTAGGCTTGGTAACGTAGCTAACGCGTGAAGTTGACCGCCTGGGGAGTACGGTCGCAAGATTAAAACTCAAAGGAATTGACGGGGACCCGCACAAGCGGTGGATTATGTGGATTAATTCGATGCAACGCGAAAAACCTTACCTACCCTTGACATGTAGCGAATATTTTAGAGATAAAATAGTGCCTTCGGGAACGCTAACACAGGTGCTGCATGGCTGTCGTCAGCTCGTGTCGTGAGATGTTGGGTTAAGTCCCGCAACGAGCGCAACCCTTGTCATTAATTGCCATCATTTAGTTGGGCACTTTAATGAGACTGCCGGTGACAAACCGGAGGAAGGTGGGGATGACGTCAAGTCCTCATGGCCCTTATGGGTAGGGCTTCACACGTAATACAATGGCGCGTACAGAGGGTTGCCAACCCGCGAGGGGGAGCTAATCTCAGAAAGCGCGTCGTAGTCCGGATCGGAGTCTGCAACTCGACTCCGTGAAGTCGGAATCGCTAGTAATCGCGGATCAGCATGTCGCGGTGAATACGTTCCCGGGTCTTGTACACACCGCCCGTCACACCATGGGAGTGGGTTTCACCAGAAGCAGATAGTCTAACCGTAAGGAGGGCGTTTGCCACGGTGAGATTCATGACTGGGGTGAAGTCGTAACAATTTA

For the purposes of the present invention, an isolated bacterial strainis one that has undergone some degree of purification from its naturalenvironment. A culture of a bacterium is considered to be biologicallypure if at least 20% of the bacteria are from one bacterial strain.However, it is preferable if the culture is at least 33% pure, morepreferable if the culture is at least 45% pure and most preferable ifthe culture is at least 90% pure.

The bacterial strains of the present invention may also be combined witheach other, other species of bacteria, nutrients and/or other componentsto provide a composition for maintaining or purifying water-containingmedia. It may be desirable, for example, to combine the bacteria of thepresent invention with bacteria capable of removing other pollutants orundesirable compounds from water-containing media. Examples of suchbacteria include nitrite-oxidizing bacteria (chemolithoautotrophicbacteria which oxidize nitrite to nitrate), heterotrophic bacteria(which mineralize organic material into ammonia and other substances)and other bacteria which will be known to those of skill in the art.Nitrite-oxidizing bacteria are known from the Nitrospira phylum ofbacteria, and the alpha, gamma and delta subdivisions of theProteobacteria. Examples include species of the genera Nitrospira,Nitrospina and Nitrobacter. Nitrate-reducing bacteria are known from thegenera Azoarcus, Pseudomonas and Alcaligenes. Heterotrophic bacteria areknown from the genera Bacillus, Planctomyces, Pseudomonas andAlcaligenes. Such are available from known sources (e.g., American TypeCulture Collection, 10801 University Blvd., Manassas Va. 20100, USA) ormay be isolated directly from aquaria biofilters.

For example, the bacterial strains of the present invention may becombined with nitrite-oxidizing bacteria such that ammonia present inthe water system would be oxidized to nitrite and the nitrite oxidizedto nitrate. Another example would be to combine the bacterial strain ofthe present invention with aerobic or anaerobic denitrifying bacteria.In this case, the nitrate which is produced by the interaction of thebacterial strains of the present invention with nitrite-oxidizingbacteria would be reduced to dinitrogen or other nitrogen basedproducts. A third example would be to combine the bacterial strain ofthe present invention with heterotrophic bacteria which mineralizeorganic matter into simpler inorganic substances which, subsequently,can be utilized as substrates by the bacterial strains of the presentinvention.

The present invention also provides a mixture comprising a concentratedbacterial strain capable of oxidizing ammonia to nitrite, wherein the16S rDNA of the bacteria has a nucleotide sequence of SEQ ID NO:1, SEQID NO:2, SEQ ID NO:3, SEQ ID NO:4, SEQ ID NO:18, SEQ ID NO:19 or SEQ IDNO:20 or a variant thereof which is at least 96% similar, at least 97%similar, at least 98% similar or at least 99% similar to SEQ ID NO:1,SEQ ID NO:2, SEQ ID NO:3, SEQ ID NO:4, SEQ ID NO:18, SEQ ID NO:19 or SEQID NO:20. According to this embodiment of the invention, the bacterialstrain is considered to be concentrated if the bacterial strain occursin a concentration which is higher than its concentration occurred innature. In general, the concentration of the bacterial strain will be atleast 20% of the total cells in the sample as determined by standardtechniques such as molecular probing using fluorescent in situhybridization (FISH) techniques, which will be known to those skilled inthe art, using appropriate controls and enumeration methods. Morepreferably, the concentration of the bacterial strain would be 33% orgreater of the total cells, even more preferably 45%, and mostpreferably 90% or greater of the total cells. However, it may bepreferable to have more than one of the bacteria which have a nucleotidesequence of SEQ ID NO:1, SEQ ID NO:2, SEQ ID NO:3, SEQ ID NO:4, SEQ IDNO:18, SEQ ID NO:19 or SEQ ID NO:20 in the mixture. In this case, thepercentages stated above relate to percentage of total AOBs in themixture with the understanding that the balance of cell population mightbe comprised of nitrite-oxidizing bacteria or other types of bacteria.

In particular, while not wishing to be bound by any theory, of thevarious bacterial strains described in accordance with the presentinvention, those strains represented by SEQ ID NO:18, SEQ ID NO:19 andSEQ ID NO:20 are believed to be especially tolerant of saltwaterenvironments; although these strains may be utilized in freshwaterenvironments, as well, and are believed to function effectively therein.Bacterial strains and mixtures incorporating strains other than thosestrains represented by SEQ ID NO:18, SEQ ID NO:19 and SEQ ID NO:20 mayalso tolerate saltwater environments to an appreciable degree, yet in apreferred embodiment of the present invention, it is those strainsrepresented by SEQ ID NO:18, SEQ ID NO:19 or SEQ ID NO:20 that areincluded in a saltwater environment to oxidize ammonia to nitrite.

Furthermore, any of the bacterial strains of the present invention maybe freeze-dried, and are believed to be particularly tolerant of thefreeze-drying process, as evidenced by their ability to remain viableafter such a process, and to oxidize ammonia to nitrite following such aprocess. Thus, in a further embodiment of the present invention, any ofthe bacterial strains described herein may be freeze-dried andthereafter used to oxidize ammonia to nitrite.

It is understood that the bacterial strains and the mixtures of thepresent invention can be in the form of powder, liquid, a frozen form, afreeze-dried form or any other suitable form, which may be readilyrecognized by one of skill in the art. These are commonly referred to as“commercial additives,” and may include, but are in no way limited to:

-   -   (1) a liquid form, wherein one or more strains are in a liquid        solution containing inorganic salts or organic compounds such        that the viability of the cells is not destroyed during the        course of storage;    -   (2) a frozen form, wherein one or more of the strains are in a        liquid mixture as above, optionally including cryoprotectant        compounds to prevent cell lysis, which is frozen and stored at a        temperature at or below 32° F.; and    -   (3) a powder form, which has been produced by freeze-drying or        other means, wherein the dehydrated form of one or more of the        strains or mixture can be stored at normal room temperature        without loss of viability.

Obtaining a proper form of the bacterial strain and the mixture of thepresent invention is well within the skill in the art in view of theinstant disclosure. It is also understood that the bacterial strains andthe mixture of the present invention can be used alone, or incombination with other components. Examples of such components include,but are not limited to, nitrite-oxidizing bacteria, heterotrophicnitrite-oxidizing bacteria, heterotrophic ammonia-oxidizing bacteria andthe like. All of the forms of the biologically pure bacterial strain mayalso contain nutrients, amino acids, vitamins and other compounds whichserve to preserve and promote the growth of the bacterial strain. Thebacterial strains and the mixtures and compositions of the presentinvention can be used in freshwater aquaria, seawater aquaria andwastewater to alleviate the accumulation of ammonia. They can also beused in a bioremediation process to reduce the level of pollution causedby the ammonia. A bioremediation process, also called bioaugmentation,includes, but is not limited to, the supplemental addition ofmicroorganisms to a system (e.g. a site where biological or chemicalcontamination has occurred) for the purposes of promoting orestablishing biological and/or chemical processes that result in thechange of one or more forms of chemical compounds present in theoriginal system.

Accordingly, one aspect of the present invention provides a method ofalleviating the accumulation of ammonia in a medium. The method includesa step of placing into the medium a sufficient amount of a bacterialstrain capable of oxidizing ammonia to nitrite to alleviate theaccumulation of ammonia in the medium, wherein the 16S rDNA of thebacteria strain has a nucleotide sequence of SEQ ID NO:1, SEQ ID NO:2,SEQ ID NO:3, SEQ ID NO:4, SEQ ID NO:18, SEQ ID NO:19 or SEQ ID NO:20 ora variant thereof which is at least 96% similar, at least 97% similar,at least 98% similar or at least 99% similar to SEQ ID NO:1, SEQ IDNO:2, SEQ ID NO:3, SEQ ID NO:4, SEQ ID NO:18, SEQ ID NO:19 or SEQ IDNO:20. The amount of the bacterial strain(s) is sufficient if the addedbacteria can alleviate or prevent the accumulation of ammonia in themedium. In general, the addition of one or more of the bacterial strainsof the invention to a freshwater or saltwater aquarium is expected toreduce the maximum ammonia concentration by at least 50% over the levelwhich would be attained in the absence of the bacterial strain(s).

It will be appreciated that the actual levels achieved in a givensetting will be a function of the size and contents of the systems(i.e., the number of fish, plants, etc.). In a newly set-up 37 literaquarium with ten fish, the ammonia concentration may reach 7 mg/L orhigher without addition of the bacterial strain, whereas the maximumlevel can be reduced to about 2 mg/L by addition of the bacterialstrain. In general, the maximum ammonia concentration would not beexpected to exceed 3 mg/L if the bacterial strain of the invention isadded to such a system. When the system reaches a steady state, theammonia levels drop back to below 0.5 mg/L, a process which occurs morerapidly when the bacterial strain of the invention is present.

In one embodiment of the present invention, the bacterial strains of thepresent invention are placed directly into a medium such as, but notlimited to, freshwater aquaria, seawater aquaria and wastewater. Inanother embodiment of the present invention, the bacteria may be grownon a rotating biological contactor and then placed in the medium. In adifferent embodiment, the bacteria of the present invention can beplaced on a biofilter unit contained in the medium. In anotherembodiment the bacteria of the present invention may be immobilized inan immobilizing polymer, such as, but not limited to, acrylamide,alginate or carrageenan. This bacterial-laced polymer material may thenbe placed in a filter or may itself be placed in the filter stream of asuitable facility.

As used herein, the term “aquarium” is intended to mean a containerwhich may be made of, in combination or in its entirety, but not limitedto, glass, plastic, or wood that holds water and in which living aquaticorganisms (such as fish, plants, bacteria and invertebrates) are placed,and the contents thereof. An aquarium may be for the purposes ofdisplaying aquatic organisms, for their short or long-term holding, forscientific study, for transportation and other purposes. A freshwateraquarium is generally an aquarium in which the liquid medium has asalinity of less than 15 parts per thousand. A saltwater aquarium isgenerally an aquarium in which the liquid medium has a salinity of morethan 15 parts per thousand. The term “aquarium water” is used to referto the medium which is contained within the aquarium, and its associatedfilter systems, in which the aquatic organisms reside. Aquarium watermay contain a wide range of inorganic or organic chemical substancesand, therefore, may have a wide range of parameters such asconcentration of salts, pH, total dissolved solids and temperature, toname a few.

As used herein, “wastewater” generally refers to a liquid medium whichis the product of an industrial or human process. It may requiretreatment by one or more filtration methods to render it less harmful tothe environment such that it conforms to discharge standards asdetermined by a governmental agency. Wastewater may also be recycledsuch that it is not discharged to the environment.

As used herein, a “biological filter,” also called a “biofilter,”generally refers to a filter type whose purpose is to promote the growthof microorganisms, or to provide a substrate for the attachment andgrowth of microorganisms. A biofilter may be part of an aquariumfiltration system or a wastewater filtration system. As used herein, theterm “rotating biological contactor” generally refers to a type ofbiofilter which rotates in the water or medium. It may be completely orpartially submerged in the water or medium. Persons skilled in the artwill recognize rotating biological contactors as embodied in U.S. Pat.Nos. 2,085,217; 2,172,067; 5,423,978; 5,419,831; 5,679,253; 5,779,885and all continuations, improvements and foreign counterparts; each ofwhich is incorporated herein by reference as if fully set forth.

As used herein, “filter floss” refers to irregularly shaped natural orsynthetic multi-stranded material which may serve as a biofilter, amechanical filter or a combination of these.

As used herein, “aquarium gravel” refers to a substrate commonly placedinside, on the bottom, of an aquarium. It may be composed of irregularor regular shaped pieces of rock, coral, plastic or other material. Itmay serve as a biofilter, a mechanical filter, for decorative purposesor a combination of these.

As used herein, the term “filter sponge” refers to a natural orsynthetic material which when used in an aquarium or as part of anaquarium filtration system may serve as a mechanical filter, a biofilteror both.

As used herein, “plastic filter media” refers to a man-made materialwhich serves as a biofilter, a mechanical filter or both. It may beplastic molded or injected molded.

In another embodiment, nucleic acid sequences and bacteria withsequences which have the nucleotide sequence of SEQ ID NO:1, SEQ IDNO:2, SEQ ID NO:3, SEQ ID NO:4, SEQ ID NO:18, SEQ ID NO:19 or SEQ IDNO:20 or a variant thereof which is at least 96% similar, at least 97%similar, at least 98% similar or at least 99% similar to SEQ ID NO:1,SEQ ID NO:2, SEQ ID NO:3, SEQ ID NO:4, SEQ ID NO:18, SEQ ID NO:19 or SEQID NO:20 are also provided.

In another embodiment, oligonucleotide probes are provided that may beused to detect the bacteria and nucleic acid sequences of the presentinvention. The oligonucleotide probes are represented by SEQ ID NO:5,SEQ ID NO:8 and SEQ ID NO:21. A sequence that is at least 96% similarover the entire length of any of the aforementioned probes may also beused to detect the bacteria of the present invention. These probes arefurther described in the ensuing examples.

In another embodiment, PCR primers are provided that may be used todetect the bacteria and nucleic acid sequences of the present invention.The PCR primer pairs are represented by SEQ ID NO:6 and SEQ ID NO:7, SEQID NO:9 and SEQ ID NO:10, SEQ ID NO:11 and SEQ ID NO:12 and SEQ ID NO:22and SEQ ID NO:23. A sequence that is at least 96% similar over theentire length of any of the aforementioned PCR primers may also be usedto detect the bacteria of the present invention. These PCR primers arefurther described in the ensuing examples.

It would be readily apparent to one skilled in the art that variants ofthe aforementioned oligonucleotide probes and PCR primers that still maybe used to detect the bacteria and nucleic acid sequences of the presentinvention are within the scope of the present invention. For example, avariant of any of the oligonucleotide probes or primers that differsfrom SEQ ID NO:5, SEQ ID NO:8, SEQ ID NO:21, SEQ ID NO:6, SEQ ID NO:7,SEQ ID NO:9, SEQ ID NO:10, SEQ ID NO:11, SEQ ID NO:12, SEQ ID NO:22 orSEQ ID NO:23 due to one or more nucleotide additions, deletions orsubstitutions, but still may be used to detect the bacteria and nucleicacid sequences of the present invention, is encompassed by the presentinvention.

The present invention includes isolated bacteria, isolated bacterialstrains, bacterial cultures and nucleotide sequences comprising thesequences identified herein as SEQ ID NO:1, SEQ ID NO:2, SEQ ID NO:3,SEQ ID NO:4, SEQ ID NO:18, SEQ ID NO:19 and SEQ ID NO:20, or variants ofthose sequences. Particularly preferred variants are those in whichthere is a high degree of similarity to SEQ ID NO:1, SEQ ID NO:2, SEQ IDNO:3, SEQ ID NO:4, SEQ ID NO:18, SEQ ID NO:19 or SEQ ID NO:20. Thepresent invention includes variants that are at least 96% similar, atleast 97% similar, at least 98% similar or at least 99% similar to SEQID NO:1, SEQ ID NO:2, SEQ ID NO:3, SEQ ID NO:4, SEQ ID NO:18, SEQ IDNO:19 or SEQ ID NO:20. It is appreciated in the art that disclosuresteaching those skilled in the art how to make and use a referencesequence (such as SEQ ID NO:1, SEQ ID NO:2, SEQ ID NO:3, SEQ ID NO:4,SEQ ID NO:18, SEQ ID NO:19 or SEQ ID NO:20) will also be sufficient toteach such an individual to make and use the described variants.

Three commonly-assigned patents describing nitrite-oxidizing bacteria,methods of using the bacteria and methods of detecting the bacteriaissued in the United States (see U.S. Pat. Nos. 6,207,440, 6,265,206 and6,268,154). All three patents describe a nucleotide sequence and anyvariants that have greater than 96.1% homology to that sequence. Theissuance of these patents demonstrates that specifications setting forthparticular sequences and describing particular variants enable oneskilled in the art to make and use the sequence and its describedvariants. In addition, it is common in the art that patents disclosingnucleotide sequences also disclose and claim variants of those sequences(see, e.g. U.S. Pat. Nos. 6,465,621, 6,509,170 and 6,573,066).

Variants of particular nucleotide sequences may be naturally-occurringpolymorphisms or synthetic sequence alterations (see, e.g., U.S. Pat.No. 6,485,938). A great diversity of modifications to nucleotidesequences, both natural and synthetic, are common and well known in theart, along with methods for making the synthetic variants (see, e.g.U.S. Pat. Nos. 6,448,044 and 6,509,170). Methods for comparing thesimilarity of two or more nucleotide sequences are well known in theart. Similar sequences are often identified using computer programs suchas BESTFIT and BLAST (see, e.g., U.S. Pat. No. 6,461,836). Further,hybridization may be used to detect the similarity between variantsequences and a reference sequence (see, e.g., U.S. Pat. No. 6,573,066).Thus, one skilled in the art would be able to easily synthesize andidentify nucleotide sequences that are variants of a reference sequenceby using known techniques. Therefore, a specification that describes anucleotide sequence and its variants allows one skilled in the art tomake and use that sequence and its variants.

EXAMPLES

A series of assays and experiments were conducted to isolate, identifyand show the efficacy of the bacterial strains reported herein. Theyinvolved a variety of bacterial culturing techniques, molecularbiological analyses of DNA extracted from samples of the cultures,molecular biological analysis of the bacterial strains, and theapplication of concentrated cultures of the bacterial strains to aquariato measure their ability to control ammonia concentrations.

Example 1 Bacteria Culturing

Bacterial culturing vessels (termed reactors) were constructed andseeded with bacterial biomass gathered from operating aquaria. Eachreactor received 4.95 L of a mineral salt solution (made up in distilledwater) containing 50 g KH₂PO₄, 50 g K₂HPO₄, 18.75 g MgSO₄.7H₂O, 1.25 gCaCl₂.2H₂O and 1 g FeSO₄.7H₂O. Air was provided such that the dissolvedoxygen was equal to or greater than 7.5 mg/L, stirring was provided, andthe reactors were kept in a darkened cabinet at approximately 28° C.

For the isolation and culturing of strains of AOB of the presentinvention in saltwater environments, synthetic seasalts (INSTANT OCEAN,Aquarium Systems Inc., Mentor, Ohio) were added to reach a saltconcentration of between 30 and 33 ppt.

The ammonia and nitrite concentrations were measured daily using flowinjection analysis (FIA, Tecator FIAStar 5010 system) while pH wasdetermined with an electrode (Denver Instruments Model 225 pH/ISE meterand associated pH/ATC electrode). Nitrate and conductivity were measuredperiodically and the data were used to determine when water changes wererequired. Bacterial biomass was retained in the reactors during waterchanges because the biomass is very floccular in nature. Thus prior todecanting 50% of the reactor's volume through the appropriate samplingport, the biomass was settled by turning off both the air and thestirring mechanism for one hour. Additionally, reactors wereperiodically scrubbed to remove the biomass from the surfaces andthereby return the biomass to suspension. Microbiological samples weretaken routinely for DNA extraction (for PCR) and cell fixation (forFISH) for further analysis.

Example 2 Nucleic Acid Sampling and Extraction

For DNA extraction, samples of appropriate biological filtration mediawere taken and resuspended in cell lysis buffer (40 mM EDTA. 50 mMTris-HCl, pH 8.3). Samples were stored at −20° C. or −74° C. untilextraction. For processing, lysozyme was added to the samples to a finalconcentration of 10 mg/ml. After incubation at 37° C. for 90 minutes,20% sodium dodecyl sulfate (SDS) was added to a final concentration of1%. Then the samples were subjected to four freeze/thaw cycles followedby the addition of proteinase K (stock concentration, 10 mg/ml) to afinal concentration of 2 mg/ml and incubated at 70° C. for 35 minutes.In some cases, additional proteinase K and SDS were added and the samplewas incubated at 55° C. for another 30 minutes.

After cell lysis, DNA was extracted using Easy DNA extraction kit(Qiagen Inc., Santa Clarita, Calif.; hereinafter “Qiagen”). DNA waseluted to a 50 μl volume and quantified by Hoechst type 33258 dyebinding and fluorometry (DynaQuant 200, Hoefer Pharmacia Biotech Inc.,San Francisco, Calif.).

Example 3 Clone Libraries of PCR Amplified rRNA Genes

Clone libraries were derived from DNA extracts from biomass samplestaken from reactors and aquaria. Bacterial ribosomal RNA gene fragmentsfrom bacteria represented by the sequences SEQ ID NO:1, SEQ ID NO:2, SEQID NO:3, SEQ ID NO:4, SEQ ID NO:18 and SEQ ID NO:20 were amplified withthe primers S-D-Bact-0011-a-S-17 (8f; GTT TGA TCC TGG CTC AG) (SEQ IDNO:13) and 1492r (eubacterial; GGT TAC CTT GTT ACG ACT T) (SEQ IDNO:14). PCR conditions, cycle parameters, and reaction components wereas previously described (DeLong, E. F. 1992. Archaea in coastal marineenvironments. Proc. Natl. Acad. Sci. USA 89: 5685-5689.) PCR productswere evaluated by agarose gel electrophoresis. PCR fragments were clonedwith a TA Cloning kit (Invitrogen, Carlsbad, Calif.), as described inthe manufacturer's directions, after rinsing with TE buffer andconcentrating to 30 μl with a CENTRICON concentrator (Amicon, Inc.Beverly, Mass.).

Example 4 Sequencing and Phylogenetic Analysis

The 16S rDNA insert from each clone that comprised the clone librarywere screened by restriction enzyme analysis (REA) using the restrictionenzyme Hae III in order to ensure that the 16S rDNA insert wasamplifiable and determine whether the 16S rDNA possessed a unique REApattern when digested with the Hae III enzyme. If a clone wasamplifiable and possessed a unique REA pattern, then the clone's plasmidcontaining the 16S rDNA insert of interest was partially sequenced. Theamplified PCR 16S rDNA template of each clone selected for sequencingwas cleaned using the PCR Purification Kit Catalog No. 28142 (Qiagen).Sequencing was performed using a LiCor 4000L automated DNA sequencer ontemplate cycle-sequenced with fluorescently labeled primers andSEQUITHERM EXCEL II DNA Sequencing kits (Epicenter Technologies,Madison, Wis.).

Up to two or three clones of the same REA pattern were partiallysequenced to ensure that they were identical. Many clones were fullysequenced and phylogenetically analyzed by PAUP (Phylogenetic AnalysisUsing Parsimony ver 4.0b2a, D. L. Swofford) (bootstrap values anddistance analysis), ARB (A Software Environment for Sequence Date, W.Ludwig and O. Strunk) (phylogenetic tree) and Phylip (PhylogenyInference Package J. Felsentein) (similarity matrix). Primers and probesfor the clone of interest from the clone libraries were developed usingARB probe design and probe match programs as well as after manualalignment. Primers and probes were double checked with BLAST (S. F.Altschul et al. 1990. Basic local alignment tool. J. Mol. Biol.215:403-410). The specificity of the primers was determined by usingthem on DNA extracted from clones and pure cultures of known bacteria.The specificity of the probes was tested using pure cultures of knownbacteria and samples from the reactors.

Example 5 DGGE Analysis and Profiling

For general eubacterial DGGE analysis, rDNA fragments were amplifiedusing the forward 358f (eubacterial; CCT ACG GGA GGC AGC AG) (SEQ IDNo:15) with a 40-bp GC-clamp on the 5′ end as described by Murray et al.(A. Murray et al. 1996. Phylogenetic compositions of bacterioplanktonfrom two California estuaries compared by denaturing gradient gelelectrophoresis of 16S rDNA fragments. Appl. Environ. Microbiol.62:2676-2680), and the reverse primer S-*-Univ-0519-a-A-18 (519r: GWATTA CCG CGG CKG CTG) (SEQ ID NO:16). For specific AOB DGGE, the forwardprimer of 358f (SEQ ID No:15) with a 40-bp GC-clamp on the 5′ end wasused with the reverse primer S-*-Ntros-0639-a-A-20 (Nitroso4e: CAC TCTAGC YTT GTA GTT TC) (SEQ ID NO:17). The PCR conditions were the same andwere performed on a ROBOCYCLER GRADIENT 96 (Stratagene, La Jolla,Calif.) using the TAQ PCR core kit (Qiagen). PCR conditions included ahot start (80° C.) and a touchdown procedure. Initial denaturation at94° C. for 3 min. was followed by a denaturation at 94° C. for 1 min., atouchdown annealing from 65° C. to 55° C. for 1 min. 29 sec. (theannealing time during the touchdown increased by 1.4 sec. per cycle) andprimer extension at 72° C. for 56 sec. (the extension time was increased1.4 sec. per cycle). The final temperature series of the above thermalcycle was repeated for 20 total cycles, followed by a final extension at72° C. for 5 min. Amplicons were examined by agarose gelelectrophoresis. DGGE was performed with a Bio-Rad D-GENE System(Bio-Rad Laboratories, Hercules, Calif.; hereinafter “Bio-Rad”). Gelswere 8.5% acrylamide/Bis using Bio-Rad reagents (D GENE ElectrophoresisReagent Kit, Bio-Rad). Gel gradients were poured using Bio-Rad reagents(D GENE Electrophoresis Reagent Kit, Bio-Rad) with a denaturing gradientof 20% to 60% (where 100% denaturant is a mixture of 40% deionizedformamide and 7 M urea) and the Bio-Rad gradient delivery system (Model475, Bio-Rad). All gels were run at 200 volts for 6 hours. Gels werevisualized in one of two ways. For visualization and recovery ofdiscrete DNA bands, gels were first stained for 10 minutes in 250 ml of1× TAE buffer in which 100 μl of ethidium bromide (1 mg/ml) was added,then washed for 10 min. in 1× TAE buffer. For documentation purposessome gels were stained in Vistra Green (diluted 1:10,000) (MolecularDynamics, Sunnyvale, Calif.; hereinafter “Molecular Dynamics”) for 20min., followed by a 20 min. wash in 1× TAE buffer, and then scannedusing a FLUORIMAGER SI (Molecular Dynamics).

Individual bands were excised from the DGGE gels usingalcohol-sterilized scalpels. Extraction of DNA from the gel followed themethods of Ferris et al. (M. J. Ferris et al. 1996. Denaturing gradientgel electrophoresis profiles of 16S rRNA-defined population inhabiting ahot spring microbial mat community. Appl.Environ. Microbiol. 62:340-346.). The excised band was placed in a sterile 2 ml screw cap tubewith 500 μl sterile deionized water. The tubes were half-filled withglass beads (cat. no.11079-101, Biospec Products Inc., Bartlesville,Okla.; hereinafter “Biospec”) and placed in a mechanical bead beater(MINI-BEADBEATER-8, Biospec) for 3 min. at the highest setting. Theprocessed DNA remained in the tubes at 4° C. overnight. After overnightstorage, the tubes were centrifuged at 3,200×g for 8 minutes at 4° C. toconcentrate the gel fragments. The supernatant was transferred to aclean eppendorf tube.

To check the extraction efficiency, the supernatant was re-amplifiedwith the DGGE primers and re-analyzed by DGGE. An extraction wasconsidered acceptable if it yielded a single band in DGGE analysis whichco-migrated with the original DGGE band in the mixed population sample.The nucleotide sequence of the excised band was sequenced by thepreviously described methods using fluorescently labeled primers.

Example 6 Oligonucleotide Probe Development

Oligonucleotide probes were designed that specifically hybridize withthe 16S rRNA gene sequence isolated from closely related bacteria fromreactors in this study. One probe (S-G-Nsspa-0149-a-A-18) (SEQ ID NO:5)targets two reactor-derived Nitrosospira-like bacteria, which arerepresented by the sequences of SEQ ID NO:1 and SEQ ID NO:2 to theexclusion of other beta subdivision Proteobacterial ammonia-oxidizersincluding the sequences represented by SEQ ID NO:3 and SEQ ID NO:4, andalso to the exclusion of Nitrosomonas aestuarii-like bacteriarepresented by SEQ ID NO:18, SEQ ID NO:19 and SEQ ID NO:20.

A second probe (S-G-Nsspa-0149-a-A-19) (SEQ ID NO:8) targets onereactor-derived Nitrosospira-like bacterium, which is represented by thesequence of SEQ ID NO:3, to the exclusion of SEQ ID NO:1, SEQ ID NO:2,SEQ ID NO:4 and other beta subdivision Proteobacterialammonia-oxidizers, and also to the exclusion of Nitrosomonasaestuarii-like bacteria represented by SEQ ID NO:18, SEQ ID NO:19 andSEQ ID NO:20.

Additional oligonucleotide probes were designed that specificallyhybridize with the 16S rRNA gene sequence isolated from other bacteriafrom reactors in this study. One probe, S-G-Ntsms-0149-a-A-18, (SEQ IDNO:21) targets Nitrosomonas aestuarii-like bacteria, which arerepresented by the sequences of SEQ ID NO:18, SEQ ID NO:19 and SEQ IDNO:20 to the exclusion of other AOB sequences represented by SEQ IDNO:1, SEQ ID NO:2, SEQ ID NO:3, SEQ ID NO:4, as well as sequences fromhalophila-like bacteria.

Probe matches were initially screened using BLAST (S. F. Altschul et al.1990. Basic local alignment tool. J. Mol. Biol. 215:403-410) andCHECK_PROBE (B. L. Maidak et al. 1994. The ribosomal database project.Nucleic Acids Res. 22:3485-3487.). Probes were synthesized by OperonTech, Inc. (Alameda, Calif.). The nucleotide sequence and position ofthe probes are shown in Table 10.

TABLE 10 The nucleotide sequences and positions of oligonucleotideprobes and PCR primer sets for ammonia-oxidizing bacteria. Base Sequence% Annealing Target Probe/Primer (5′ to 3′) formamide Temp (° C.) GroupS-G-Nsspa-0149-a-A-18 CCC CCC TCT TCT 30 — SEQ ID NO: 1 & (SEQ ID NO: 5)GGA TAC SEQ ID NO: 2 S-G-Nsspa-0149-a-A-19 TCC CCC ACT CGA 20 — SEQ IDNO: 3 (SEQ ID NO: 8) AGA TAC G S-G-Ntsms-0149-a-A-18 TCC CCC ACT TCT 20— SEQ ID NO: 18, (SEQ ID NO: 21) GGA CAC SEQ ID NO: 19 & SEQ ID NO: 20Forward primer CGG AAC GTA TCC — 54 SEQ ID NO: 1 & (SEQ ID NO: 6) AGAAGA SEQ ID NO: 2 Reverse primer ATC TCT AGA AAA — (SEQ ID NO: 7) TTC GCTForward primer ATC GGA ACG TAT — 56 SEQ ID NO: 3 (SEQ ID NO: 9) CTT CGReverse primer CCA CCT CTC RGC — (SEQ ID NO: 10) GGG C Forward primerTCA GAA AGA AAG — 56 SEQ ID NO: 4 (SEQ ID NO: 11) AAT CAT G Reverseprimer GTC TCC AYT AGA — (SEQ ID NO: 12) TTC CAA G Forward primer GTGACT AAT AAT — 56 SEQ ID NO: 18, (SEQ ID NO: 22) CAC AAC TTA SEQ ID NO:19 & SEQ ID NO: 20 Reverse primer TTA TCT CTA AAA — (SEQ ID NO: 23) TATTCG CT

The stringency for the probes (SEQ ID NO:5, SEQ ID NO:8 and SEQ IDNO:21) was determined though a series of FISH experiments at differingformamide concentrations using the reactor biomass as a positive controlfor the bacterial sequences herein (SEQ ID NO:1, SEQ ID NO:2, SEQ IDNO:3, SEQ ID NO:4, SEQ ID NO:18, SEQ ID NO:19 or SEQ ID NO:20). Thespecificity of the probes was examined by testing against negativecontrol cells of pure cultures of other beta subdivisionammonia-oxidizing bacteria (Nitrosomonas europaea, Nitrosospiramultiformis, Nitrosomonas cryotolerans). In situ hybridization of thefixed, immobilized cells was carried out in a hybridization solutionconsisting of 0.9 M NaCl, 20 mM Tris/HCl (pH 7.4), 0.01% sodium dodecylsulphate (SDS), 25 ng of oligonucleotide probe, and varying amounts offormamide. Slides were incubated in an equilibrated humidity chamber at46° C. for 90 to 120 min. The hybridization solution was rinsed off witha prewarmed (48° C.) wash solution. The slides were then incubated inthe wash solution for 15 min. at 48° C. To achieve the same stringencyduring the washing step, as in the hybridization step, the wash solutioncontained 20 mM Tris/HCl (pH 7.4), 0.01% SDS, 5 mM EDTA, and NaCl. Theconcentration of NaCl varied according to the percent formamide used inthe solution. For 20% formamide the NaCl concentration was 215 mM, for30% it was 120 mM, and for 40% the NaCl concentration was 46 mM. Cellswere detected using an AXIOSKOP 2 epifluorescence microscope (CarlZeiss, Jena, Germany) fitted with filter sets for FITC/FLUO3 and HQ CY3.The optimum stringency was determined to be 30% formamide for theS-G-Nsspa-0149-a-A-18 probe. For the S-G-Nsspa-0149-a-A-19 probe theoptimum stringency was determined to be 20% formamide. The optimumstringency was determined to be 20% formamide for the probe representedby SEQ ID NO:21, and 20% formamide for the probe represented by SEQ IDNO:24.

Example 7 PCR Primer Development

Two sets of PCR primers were developed which specifically detectNitrosospira-like bacteria of the sequences of the present invention. Athird set of PCR primers was developed which specifically detectsNitrosomonas-like bacteria of the sequences of the present invention.One set (SEQ ID NO:6 and SEQ ID NO:7) specifically detectsNitrosospira-like bacteria with the sequence SEQ ID NO:1 and sequenceSEQ ID NO:2 to the exclusion of other ammonia-oxidizing bacteria (Table11). The second set (SEQ ID NO:9 and SEQ ID NO:10) specifically detectsthe Nitrosospira-like bacteria with the sequence SEQ ID NO:3 to theexclusion of other ammonia-oxidizing bacteria (Table 11). The third set(SEQ ID NO:11 and SEQ ID NO:12) specifically detects theNitrosomonas-like bacteria with the sequence SEQ ID NO:4 to theexclusion of other ammonia-oxidizing bacteria (Table 11).

A fourth set (SEQ ID NO:22 and SEQ ID NO:23) specifically detect theNitrosomonas aestuarii-like bacteria with the sequences SEQ ID NO:18,SEQ ID NO:19 and SEQ ID NO:20 to the exclusion of otherammonia-oxidizing bacteria. PCR conditions were as previously describedexcept the annealing temperature was modified.

TABLE 11A Results of the PCR primer development specificity testing andannealing temperature experiments. Type A Type B Type C AOB PCR AOB PCRAOB PCR SEQ ID NO: 6 SEQ ID NO: 9 SEQ ID NO: 11 Clone Number or and andand Bacteria Species SEQ ID NO: 7 SEQ ID NO: 10 SEQ ID NO: 12 AnnealingTemp. (° C.) 48 50 52 54 54 56 58 60 48 50 52 54 56 R7c140(TypeA) + + + + − − − − − − − − − R7c187 (TypeA) + + + + − − − − − − − −− R3c5 (TypeB) − − − − + + + + − − − − − R5c20 (TypeB) − − − − + + + + −− − − − R3c12 (TypeC) − − − − − − − − + + + + + R5c47 (TypeC) − − − − −− − − + + + + + N. europaea − − − − − − − − − − − − − N. multiformis − −− − − − − − +/− +/− +/− − − N. cryotolerans − − − − − − − − − +/− + +/−− P4c42 − − − − − − − − − − − − − P4c31 − − − − − − − − − − − − −BF16c57 − − − − − − − − − − − − − Negative control − − − − − − − − − − −− − Weak (+/−), Strong (+) or No Signal (−)

TABLE 11B Results of the PCR primer development specificity testing andannealing temperature experiments. SEQ ID NO: 22 Clone Number or andBacteria Species SEQ ID NO: 23 Annealing Temp. 48 50 52 54 (° C.) R7c140(TypeA) − − − − R7c187 (TypeA) − − − − R3c5 (TypeB) − − − − R5c20(TypeB) − − − − R3c12 (TypeC) − − − − R5c47 (TypeC) − − − − N. europaea− − − − N. multiformis − − − − N. cryotolerans − − − − P4c42 − − − −P4c31 − − − − BF16c57 − − − − Negative control − − − − Weak (+/−),Strong (+) or No Signal (−)

The specificity of each primer set was optimized by conducting a PCRexperiment with each primer set using the temperature gradient mode ofthe Stratagene ROBOCYCLER. In this mode one can run a single experimentof all the reactions at up to 12 different annealing temperatures.Typically, the experiments were conducted at 4 to 6 differenttemperatures with 2° C. increasing interval. Each PCR primer set wastested against clone product with a nucleotide sequence of SEQ ID NO:1,SEQ ID NO:2, SEQ ID NO:3, SEQ ID NO:4, SEQ ID NO:18, SEQ ID NO:19 andSEQ ID NO:20. rDNA extracted from pure cultures of Nitrosomonaseuropaea, Nitrosolobus multiformis and Nitrosomonas cryotolerans, werealso tested. Table 10 presents the PCR primer sets, and the optimalannealing temperature results are shown in Table 11.

Example 8 Similarity Analysis

Thirteen clone libraries were constructed from a number of freshwaterand saltwater nitrifying biomasses in order to determine the identity ofthe ammonia oxidizer(s) responsible for oxidation of ammonia to nitrite.Details about the biomasses are presented in Table 12.

TABLE 12 Details regarding the reactors and aquaria from which biomasswas extracted and clone libraries was constructed. Clone library Detailsof Nitrifying Biomass Biofarm 16 This biomass was retrieved from thesump of BF16. The biofarm was routinely dosed 300 mg/L/hr of ammonia(NH₃—N) for 6 hours per day. BC5 This biomass was kept in an aquarium(seeded from a freshwater biofarm) and dosed 5 mg/L or less of ammoniaevery two or three days. The aquarium was not aerated. BC5(2) Same asBC5 (above). R3 This was seeded from an enriched ammonia oxidizingculture (approx 1000 mg/L NH₃—N) that had been stored for 11 months.Grown at   5 mg/L NH₃—N and aerated. R7 This was seeded from R1 whichhad been seeded from BC5. Both R1 and R7 were kept below 5 mg/L ammonia(NH₃—N) and aerated. R7BA6 This biomass was recovered from a BacterialAdditive test that was inoculated with R7 biomass. R5 This biomass wasderived from the biofarm feed microfilter. It was exposed to extremelyhigh concentrations of ammonia (>500 mg/L NH₃—N). The reactor wasoperated at 30 mg/L ammonia (NH₃—N) and aerated. R17 This biomass wasderived from R7 but fed at 30 mg/L for a period of three weeks beforebeing returned to 5 mg/L ammonia, aerated. R13 This biomass was derivedfrom the BC5 biomass but did not appear to have any Nitroso- bacteria byusing general AOB primers. It was grown at 5 mg/L (NH₃—N) and aerated.R29 This biomass was retrived from the sump of biofarm 5 which was asaltwater biomass whose salinity was maintained at between 30 and 35ppt. This reactor was fed at 30 mg/L ammonia-nitrogen. P4 This reactorwas seeded with 20 liter of material from the sump of biofarm 15 whichwas a saltwater biomass whose salinity was maintained at between 30 and35 ppt. This reactor was fed at 5 mg/L ammonia-nitrogen. SB7 Thisreactor was seeded with material from the sumps of biofarm 5 and 15which were saltwater biomasses whose salinity was maintained at between30 and 35 ppt. This reactor was fed at 5 mg/L ammonia-nitrogen. B7 Thisreactor was seeded with material from the sumps of biofarm 5 and 15which were saltwater biomasses whose salinity was maintained at between30 and 35 ppt. This reactor was fed at 5 mg/L ammonia-nitrogen.

The clone library data show that there are three groups of ammoniaoxidizing bacteria that exist in the low ammonia feed reactors (e.g.,R3, R7). Not all three AOB types were found to exist in every reactorthough. The three bacteria are represented by three AOB clone groups—AOBType A (SEQ ID NO:1) (and a subtype A1 (SEQ ID NO:2)), and AOB Type B(SEQ ID NO:3). A fourth clonal type was found in high ammonia feedreactors—AOB Type C (SEQ ID NO:4).

A similarity ranking was conducted for the four clonal sequences usingRDP (Maidak, B. L., J. R. Cole, C. T. Parker, Jr, G. M. Garrity, N.Larsen, B. Li, T. G. Lilburn, M. J. McCaughey, G. J. Olsen, R. Overbeek,S. Pramanik, T. M. Schmidt, J. M. Tiedje and C. R. Woese. A new versionof the RDP (Ribosomal Database Project). Nucleic Acids Res. 27:171-173(1999)) (Table 8). The similarity analysis showed that AOB Type A (SEQID NO:1) and Type A1 (SEQ ID NO:2) are 99.6% similar. This agrees withthe 16S rDNA data which showed there to be 5 mismatches in the 16Sr DNAbetween the type sequence for Type A (SEQ ID NO:1) and the type sequencefor Type A1 (SEQ ID NO:2). The similarity analysis showed that the TypeA and A1 sequences are significantly different from known AOBs of eitherthe Nitrosospira or Nitrosomonas clades (Table 13). This result isfurther supported by the Bootstrap analysis which shows that the AOBType A (SEQ ID NO:1) and Type A1 (SEQ ID NO:2) cluster together in agroup that is distinct from either the Nitrosospira or Nitrosomonasclades (FIG. 1). Thus the bacteria represented by AOB Type A (SEQ IDNO:1) and Type A1 (SEQ ID NO:2) are at least new species.

TABLE 13 Similarity ranking for the ammonia-oxidizing clones isolatedfrom reactors and aquaria rDNA source % Similarity to rDNA of: Type AType A1 Type B Type C Nitro- Nitro- Nitro- Nitro- Nitro- Nitro- Nitro-Nitro- Nitro- Nitro- spira- spira- spira- somonas- somonas sovibriosolobus sospira somonas sococcus like like like like marina tenuismultiformis briensis europaea mobilis Type A — Nitrosospira- like TypeA1 0.996 — Nitrosospira- like Type B 0.944 0.942 — Nitrosospira- likeType C 0.934 0.932 0.925 — Nitrosomonas- like Nitrosomonas 0.954 0.9550.928 0.932 — marina Nitrosovibrio 0.948 0.946 0.988 0.926 0.932 —tenuis Nitrosolobus 0.948 0.946 0.984 0.927 0.937 0.989 — multiformisNitrosospira 0.941 0.940 0.971 0.919 0.936 0.979 0.980 — briensisNitrosomonas 0.936 0.935 0.925 0.984 0.932 0.931 0.933 0.925 — europaeaNitrosococcus 0.942 0.939 0.921 0.962 0.930 0.928 0.931 0.930 0.962 —mobilis Marine P4c31 P4c42 BF16c57 R7c140 Nsm. Nsm. Nsm. bact. Nsm. sp.Nsm. Nsm. Nsm. sp. Nsm. sp. halophila aestuarii marina NO3W NM51aest.-like aest.-like AF386746 AF386753 AF272413 AF272420 M96400 AF33820AF272424 P4c31 — Nsm. aestuarii- like P4c42 0.966 — Nsm. aestuarii- likeBF16c57 0.972 0.976 — Nsm. sp. (AF386746) R7c140 0.981 0.981 0.983 —Nsm. sp. (AF386753) Nsm. 0.914 0.914 0.916 0.947 — halophila (AF272413)Nsm. 0.983 0.977 1.000 0.983 0.916 — aestuarii (AF272420) Nsm. marina0.971 0.971 0.973 0.971 0.937 0.973 — (M96400) Marine bact. 0.994 0.9940.996 0.980 0.944 0.996 0.974 — NO3W (AF33820) Nsm. sp. 0.951 0.9590.982 0.979 0.915 0.982 0.989 0.981 — NM51 (AF272424)

The similarity analysis for the AOB Type B (SEQ ID NO:3) shows that thisbacterium falls into Nitrosospira clade of AOB (Table 13). Bootstrapanalysis confirms this result (FIG. 1).

However, the organism is distinct enough from the closest NitrosospiraAOB (Nitrosovibrio tenuis) that it may be considered as a new species.

The similarity analysis for the AOB Type C (SEQ ID NO:4) shows that thisbacterium falls into Nitrosomonas clade of AOB (Table 13). Bootstrapanalysis confirms this result (FIG. 1). However, the organism isdistinct enough from the closest Nitrosomonas AOB (Nitrosomonaseuropaea) that it may be considered as a new species.

The similarity analysis for the saltwater tolerant AOB we isolated whichare Nitrosomonas aestuarii-like reveals clone P4c31 (SEQ ID NO:19) to be98.3% similar to Nitrosomonas aestuarii and clone P4C42 (SEQ ID NO:18)is 97.7% similar to Nitrosomonas aestuarii. Phylogenetic analysisdemonstrates the uniqueness of the sequences represented by clones P4C42(SEQ ID NO:18) and P4c31 (SEQ ID NO:19) (FIG. 6).

The similarity rankings given in Table 13 are a guide to determining theuniqueness of one bacterial strain to another. There are no hard andfast rules regarding what percentage constitutes a new species. However,Nitrosolobus multiformis and Nitrosovibrio tenuis which have asimilarity ranking of 0.989 are recognized by all microbiologicalauthorities as distinct species, as are Nitrosolobus multiformis andNitrosospira briensis (similarity ranking of 0.980). Since thesimilarity values of the bacterial strains reported herein are nothigher than those for the above mentioned species pairs this is furtherevidence that the strains herein are novel and unique.

Therefore, the totality of the clone data, the PCR results, thephylogenetic analysis, the DGGE data and similarity ranking demonstratethat the bacterial strains reported herein are unique and distinct fromknown ammonia-oxidizing bacteria. Further, we expect that additionalwork in micro (or specialized) environments such as presented hereinwill result in the discovery of additional AOB related to the strainsreported herein.

Example 9 Analysis of Bacteria and Experimental Results

Clonal members of Type A AOB (SEQ ID NO:1 and SEQ ID NO:2) were found inboth the BF16 biomass (9% of clone library) and the BC5 biomass (1-2% ofclone library) (FIG. 2). The BC5 biomass was used to seed the lowconcentration ammonia reactor (R1), which was used to seed R7. The R7clone library generated from the R7 biomass containing only Type A AOBclones (SEQ ID NO:1 and SEQ ID NO:2) (7% of the clone library) (FIG. 2).Hence Type A AOB bacteria have been successfully subcultured from thefreshwater Biofarm to the BC5 tank and then in the R7 reactor via the R1reactor. This demonstrates the ability to successively culture thebacteria and to maintain a viable culture of AOB with the sequencesherein. Further, it demonstrates the ability to selectively enrich forthe Type A AOB as the percent of this bacterium increased from 1-2% inthe BC5 clone library to 7% in the R7 library.

Outwardly, the operation of the three systems (BioFarm 16, BC5 tank, andR7 reactor) would appear to be quite different (see Table 12). However,there is a common set of physicochemical conditions that may explain thepresence of Type A AOBs in these systems. Although the Biofarm receiveshigh concentrations of ammonia initially, it is allowed a period of timefor the ammonia concentrations to fall to low levels (below 5 mg/LNH₃—N), thus allowing the Type A bacteria to be retained in the system,exploiting a particular physiological niche of being able to grow atvery low ammonia concentrations (<5 mg/L NH₃—N). Similarly, the BC5 tankand the R7 reactor were both fed and maintained at ammonia levels at orbelow 5 mg/L NH₃—N. The Type A AOB bacteria may be able to exist atammonia concentrations above 5 mg/L NH₃—N but it is apparent that athigher concentrations of ammonia they are outcompeted by other types ofAOBs (i.e., Type B (SEQ ID NO:3) and/or Type C (SEQ ID NO:4)) asevidenced by these types of AOB being present, and Type A AOB beingabsent, in the reactors maintained at high ammonia concentrations (Table14) (FIG. 2).

The R7 biomass did particularly well in the bacterial additives test VI(BA6) and VII (BA7) (discussed below) as did a biomass grown in the samefashion (R19) and with the same seed (R1) in bacterial additives testVIII (BA8) (R19). Type A AOBs have been found in a number of reactorsand a number of Post BA test biomasses both by specific Type A AOB PCRand FISH tests (Table 14) (FIG. 2).

Therefore, these two newly discovered bacteria Type A AOB (SEQ ID NO:1)and Type A1 (SEQ ID NO:2) predominate in low ammonia concentrationenvironments, such as aquaria; and, when added to such an environment ina more purified state than they naturally occur, can accelerate theestablishment of ammonia oxidation in such an environment (discussedbelow).

Clonal members of Type B were found in the freshwater BioFarm biomasses(e.g., BF 16-34% of clone library) used to seed the BC tanks (BC5). TypeB AOB bacteria were absent in the BC5 and R7 clone libraries, indicatingthat these AOBs may be more suited to the high ammonia conditions andfeeding regime of a Biofarm (FIG. 2). Type B AOBs were also found in theR3 clone library (19% of clone library) (FIG. 2). The history of the R3reactor is that its biomass was initially enriched at high ammoniaconcentrations (3000 mg/L NH₃—N), stored for 11 months and then maturedin the reactor at low ammonia concentrations (5 mg/L NH₃—N) for anextended period of time. During the initial culturing period it waslikely that the ammonia concentrations would decrease over time—thusencouraging the growth of Type C and/or Type B AOBs over Type A AOBs.During the eleven months of storage the ammonia would be likely to beexhausted possibly encouraging the maintenance of Type B AOB bacteria inthe system and the survival of residual Type A AOBs that had survivedduring the culturing phase. Finally during the maturation period in thereactor, the Type B AOB bacteria would be able to be maintained, Type AAOBs would be enriched and any residual Type C that had been originallyselected for in the original culturing phase would be outcompeted anddisappear.

In comparison, the Biofarm's biomass receives a relatively highconcentration of ammonia for a set period of time and then allowed togradually deplete this over time, creating both a gradient of high tolow ammonia concentrations (encouraging the growth of Type B AOBs),often reaching zero thus allowing a window for the growth of Type AAOBs—low ammonia concentrations. This is a more rapid cycle (daily) thanthe culturing phase of the R3 biomass, but none the less consistent witha change of conditions from high to low ammonia concentrations withinthe biomass. Thus the gradient of ammonia concentrations in theBiofarm's biomass encourages the enrichment of a range of AOB types asconfirmed by the clone library data and the results of the DGGE tests.

Type B AOBs have been found in a number of reactors and a number of PostBA test biomasses both by specific Type B AOB PCR, DGGE and FISH.However, it has not been found in as many post bacterial additive testsor clone libraries as Type A AOB (Table 14). It seems to be that if TypeA AOB was inoculated into a test it was often recovered whereas Type BAOBs were only recovered in systems where Type A AOBs were notoriginally in the innoculum. Therefore, Type A AOBs are preferentiallygrown in the systems when they are present but Type B AOBs will sufficewhen Type A AOBs are absent.

While Type A AOBs are the most important member of a successfull AOBnitrifying community for low ammonia environments such as aquarium, theyare not the only AOB present. Other AOB, such as Type B (SEQ ID NO:3),may be necessary for the system to efficiently cope with fluctuatingconcentrations of ammonia even over short (days) periods of time.

Type C AOBs are not desirable as an AOB in a bacterial additive for thelow ammonia concentrations typically found in an aquarium. Type C AOBbacteria were not found in the BF16, BC5 or R7 clone libraries which arelow ammonia concentration environments, indicating that they were likelygrown under conditions other than that found in these three environments(FIG. 2). Type C bacteria were found in the R5, R3 and R17 clonelibraries (FIG. 2). The R5 biomass was grown consistently at highconcentrations (30 mg/L NH₃—N) and its seed was from a very high ammoniaconcentration (>500 mg/L NH₃—N), R3's biomass had been originally grownat a high ammonia concentration before being moved to a lower ammoniaconcentration (5 mg/L NH₃—N) and the R17 biomass was moved from a low (5mg/L NH₃—N) to a high ammonia concentration (30 mg/L NH₃—N) and thenback again.

The R5 biomass had been enriched at high ammonia concentrations for along period of time even before being transferred to the R5 reactor, ineffect excluding the growth of any Type A AOB bacteria as theconcentration of ammonia never dropped to low levels in the feedmicrofilter. When the biomass was transferred to R5 and theconcentration of ammonia was reduced to lower levels Type B AOB wereenriched for and became the dominant AOB in this culture. The Type Cbacteria would represent the bacteria enriched for initially in themicrofilter and then remained in the R5 biomass when the feed was keptat relatively high ammonia concentrations (30 mg/L NH₃—N).

The R3 biomass had been initially allowed to grow at high ammoniaconcentrations but over time the ammonia would become exhausted. Thisregime initially encourages the growth of Type C AOBs (at higher ammoniaconcentrations) and Type B AOBs (as the ammonia was utilized). Further,these pressures would not allow for the enrichment of Type A AOB whichare dependent on consistently low levels of ammonia. During theoperation of the R3 reactor at lower ammonia concentrations, Type C AOBbacteria would be enriched against and Type B would still survive butsince Type A AOB bacteria were originally minimized in the initialenrichment there would be very few left to take advantage of the newconditions within the reactor. Therefore, Type B AOB would be expectedto be the dominant AOB in this environment.

The R17 biomass shows typically what not to do for culturing Type Aand/or B AOBs. The R17 biomass was derived from the R7 biomass butcultured for 3 weeks at elevated ammonia (30 mg/L NH₃—N) concentrationsto see if a shift in the microbial community would occur. A shift didoccur and Type C AOBs became dominant, as demonstrated by the results ofFISH, PCR and DGGE experiments. Furthermore, the shift was irreversible.After moving the biomass back to a low ammonia concentration (5 mg/LNH₃—N) environment, the Type C AOB still remained the dominant AOB whileType A and Type B AOBs could not be detected by either FISH or DGGE.This suggests that during the three week period Type A and B AOBs wereexcluded from the R17 biomass. The R17 biomass did poorly in thesubsequent BA VIII test suggesting that Type C AOBs are not the correcttype of AOB required for an effective bacterial additive to be used inthe relatively low ammonia environment of an aquarium. This conclusionis further supported by the results of the bacterial additive testswhich showed that existing commercial bacterial mixtures which containNitrosomonas lade AOBs are not effective for accelerating theestablishment of nitrification in aquaria (discussed below).

The Type C bacteria are very closely related phylogenetically to thosebacteria that have been found in wastewater treatment plants which alsoreceive ammonia concentrations of around 30 mg/L NH₃—N (similar to R5).

The PCR primer sets described herein were used to detect the presence orabsence of the AOB strains reported here in a variety of environments.The environments include pre bacterial additive test mixtures, postbacterial additive test aquaria filters, and commercial mixtures ofnitrifying bacteria manufactured and sold by other companies. Inaddition, DNA extracted from the pure culture of other AOB was tested.

The results of these experiments are summarized in Table 14. The datashow that the PCR primer groups are specific for the bacterial strainreported herein and allow one to detect each strain exclusive of theother strains. Further, pure cultures of known AOB are not amplifiedwith any of the PCR primer sets reported herein. This demonstrates thatthe bacteria reported herein can be distinguished from known AOB.

The data also show that one would expect the commercial additivescurrently on the market to fail in accelerating the establishment ofnitrification in newly set-up aquaria because these additives do notcontain the correct species of bacteria (further detailed in thefollowing section).

Example 10 Denaturing Gradient Gel Electrophoresis Survey of Clones andReactors

The novelty of various bacterial strains reported herein is furtherdemonstrated by the results of the denaturing gradient gelelectrophoresis (DGGE) testing. FIG. 3 shows the DGGE results for twoclone representatives for each of the Type A AOB (SEQ ID NO:1), Type A1AOB (SEQ ID NO:2), Type B AOB (SEQ ID NO:3) and Type C AOB (SEQ ID NO:4)in a general eubacterial DGGE. The bacterial sequence of each AOB Typedescribed herein denatures at a different position in the gel. This isindicative of uniqueness and provides another means by which todistinguish each AOB Type from one another and also from known AOB. Noneof the bacterial sequences noted above co-migrated with Nitrosomonaseuropaea, Nitrosospira multiformis or Nitrosomonas cryotolerans (FIG.3). Furthermore, DGGE analyses of biomass extracted from variousreactors confirmed the results of the PCR and FISH testing.

FIG. 7 presents DGGE results that further distinguish the various AOBstrains of the present invention. Bands representing Nitrosomonasaestuarii-like clones P4c42 and P4c31 (SEQ ID NO:18 and SEQ ID NO:19) donot co-migrate with bands representing the strains of AOB of Type A AOB(SEQ ID NO:1), Type B AOB (SEQ ID NO:3), Type C AOB (SEQ ID NO:4) andNitrosomonas aestuarii-like clone BF16c57 (SEQ ID NO:20). None of thesestrains co-migrated with Nitrosomonas europaea, Nitrosospira multiformisor Nitrosomonas cryotolerans (FIG. 7).

Example 11 Bacterial Additive Tests

A series of experiments were conducted to determine the efficacy ofvarious bacterial mixtures containing the bacterial strains of thepresent invention as compared to: (1) control aquaria that did notreceive a mixture, (2) aquaria that were inoculated with bacterialmixtures for use in tropical fish aquaria, and (3) preserved or storedbacterial mixtures of the bacterial strains of the present invention.

Effectiveness of a mixture is demonstrated by showing that theammonia-oxidizing bacterial strains of the present invention oxidizeammonia in aquaria and, further, that when combined with otherbacterial. strains (e.g., nitrite-oxidizing bacteria), the bacteriaaccelerate the establishment of nitrification in aquaria. Establishmentof nitrification can be measured in at least three different ways. Thefirst is by counting the number days it takes after establishing a newaquarium for the ammonia and nitrite concentrations in the aquariumwater to reach a near 0 mg/L concentration. In a newly set-up freshwateraquarium, it typically takes about 14 days for the ammonia concentrationto reach 0 mg/L and about 30 to 35 days for nitrite to reach 0 mg/L.

A second way to measure the beneficial action of adding nitrifyingbacterial strains to aquaria is to compare the maximum concentration ofammonia or nitrite reached before the concentration drops to 0 mg/L. Ifthe maximum concentration of ammonia or nitrite reached in aquaria inwhich nitrifying bacteria were added is significantly less than themaximum concentration reached in control aquaria, then a degree ofeffectiveness is demonstrated.

A third way to evaluate the effectiveness of nitrifying bacterialstrains and mixtures that incorporate them is to combine the first twomethods to form a toxicity exposure curve. This type of curve accountsfor both the duration (time in days) and the degree/intensity of theexposure. In accordance with embodiments of the present invention, thiscurve is generated by plotting the concentration of the toxin over time.The area of the curve may then be determined for each treatment andtoxin by standard computational methods (e.g., by mathematicallyintegrating the curve). The treatments of each test are then compared toone other and to the control of the same test. The control curve areacan be given an arbitrary value of 1 and the other areas may thereafterbe calculated as a ratio to the control area. As such, if the value of atreatment is greater than 1 it is deemed more effective than thecontrol, while a value of less than 1 suggests that it is less effectivethan the control and may have inhibited the establishment ofnitrification.

Example 12 Bacterial Additive Test VI

The goal of this test was to evaluate the ability of four bacterialmixtures, including bacterial strains of the present invention, toaccelerate the establishment of nitrification in freshwater aquaria. Thetest was also conducted to compare an ability to establish nitrificationamong the bacterial strains of the present invention and control aquariawhich did not receive a bacterial inoculation of any kind.

Twenty-seven ten-gallon aquaria and twenty-seven Penguin 170B(Marineland Aquarium Products) hang-on-the-back style power filters weresterilized, thoroughly rinsed, and allowed to air dry. Each aquarium wasthen filled with 10 lbs of rinsed aquarium gravel (RMC Lonestar #3) andthe filter installed. The aquaria then received 35 1 of city tap waterwhich had been filtered through activated carbon. After turning thefilters on, the water level on each aquaria was marked so all could betopped-off with deionized water (DI) to account for any water loss dueto evaporation and sampling. The filters ran overnight prior to theaddition of the bacterial additives and fish.

On day 0 of the test, the aquaria were topped off with DI water and abaseline water sample taken for analysis. Carbon cartridges (MarinelandAquarium Products, Part No. PA 0133) were rinsed with tap water andplaced in each filter. New BIOWHEELS (Marineland Aquarium Products, PartNo. PR 1935B) were placed in each filter. After thirty minutes each tankwas inoculated with its designated bacterial additive, or, if the tankwas a control aquarium, it was not dosed with a bacterial mixture.

Thirty minutes after the experimental bacterial additives were added, asecond set of water samples were taken for analysis. Five rosy barbs(Puntius conchonius) and one giant danio (Danio aequipinnatus) were thenadded to each tank. The fish were fed approximately 0.4 grams oftropical fish flake split into two feedings per day (at approximately9:00 a.m. and 4:30 p.m.).

Water samples were collected and analyzed tested daily for pH, ammonia,nitrite and conductivity. On Monday, Wednesday and Friday the water wastested for nitrate and turbidity. Anions and cations were measuredperiodically. Measurements for pH were made with a Denver InstrumentsModel 225 pH/Ion meter equipped with a Denver Instruments pH combinationelectrode. A Tecator FIAstar 5010 Analyzer was used to measure ammonia,nitrite and nitrate (i.e., as nitrogen) using methods described inTecator Application Notes. Cations (sodium, ammonium-nitrogen,potassium, magnesium and calcium) were analyzed using a Dionex DX500System with a CS15 4-mm Analytical Column. Specific conductance wasmeasured directly in each tank at approximately 12:30 p.m. daily using aYSI Model 30 hand-held salinity, conductivity and temperature system.Turbidity data was determined with a DRT-100 turbidity meter (HFScientific).

Four bacterial mixtures were used in this test, and two dosing levelswere implemented within each treatment: either 30 ml or 100 ml of amixture per aquarium. Three replicates of each mix/dose combination weretested, along with three control aquaria which did not receive abacterial mixture; totaling 27 test aquaria (i.e., (4×2×3)+3=27).Conditions for the various bacterial mixtures were as follows:

1) BC5—a bacterial mixture which had been under culture for 553 dayspreceding the test. A positive result with this mixture woulddemonstrate the long-term viability of the bacteria under cultureconditions and the appropriateness of the culture techniques;

2) Rtr3—a bacterial mixture which had been bottled and stored in thedark for 118 days preceding the test. A positive result with thismixture would demonstrate that the storage method is valid and themixture retains its viability for at least 119 days of storage;

3) Rtr4—a bacterial mixture which had been bottled and stored in thedark for 118 days preceding the test. A positive result with thismixture would demonstrate that the storage method is valid and themixture retains its viability for at least 119 days of storage;

4) Rtr7—a bacterial mixture which had been grown from an inoculum fromBC5. A positive result with this mixture would demonstrate that one canculture the bacterial consortium in the mixture for successivegenerations and it maintains its viability.

The test continued for 23 days, at the termination of which the ammoniaand nitrite concentrations in the aquaria were virtually 0 mg/L. Therewere significant differences among the mean highest ammonia and nitriteconcentrations for the various aquaria, as well as the length of timenecessary for the aquaria to reach a 0 mg/L concentration. Otherdifferences between the bacterial mixtures are depicted in Table 11.

TABLE 14 Detection of Ammonia-Oxidizing Bacteria Type A Type B Type CAOB AOB AOB Template PCR PCR PCR R7c140 (TypeA) +++ − − R7c187 (TypeA)+++ − − R3c5 (TypeB) − +++ − R5c20 (TypeB) − +++ − R3c12 (TypeC) − − +++R5c47 (TypeC) − − +++ N. europaea − − − N. multiformis − − − N.cryotolerans − − − BC5 Pre BA 6 − − − BC5 Post BA 6 + − − R3 Pre BA6 + ++/− R3 Post BA 6 + +/− − R4 Pre BA6 + + − R4 Post BA 6 ++ − − R5 Pre BA7 − ++ ++ R5 Post BA7 − − − R7 Pre BA6 ++ + − R7 Post BA 6 ++ − − R7 PreBA7 + +/− − R7 Post BA7 ++ − − Cycle − − − Fritzyme − − − Stresszyme − −− Cryst Clr Nitrifier − − − Cryst Clr Bio Clar L − − − Cryst Clr BioClar S − − − Acqmar Phospaht − − − Trop Sci Sludge − − − Trop Sci RapidAct − − − +++ very strong presence, clearly indicates high amount oftarget organism ++ strong presence, indicates significant detection ofsignal + clear presence, signal detected =/− possible presence, signalweak but above background − no presence/signal detected

TABLE 15 Results of Bacterial Additives Test VI. Mean Maximum Time to≦0.50 Concentration Bacterial mg/L (days) (mg/L-N) Mixture AmmoniaNitrite Ammonia Nitrite Rtr7 - 100 ml 6 7 1.1 1.4 Rtr3 - 100 ml 7 11 1.93.4 Rtr7 - 30 ml 7 10 1.9 3.7 BC5 - 100 ml 8 18 2.4 4.5 Rtr4 - 100 ml 88 2.7 0.6 Rtr3 - 30 ml 9 15 3.1 5.9 Rtr4 - 30 ml 9 10 2.9 2.1 BC5 - 30ml 10 21 4.1 8.9 Control 12 23 4.9 13.4

FIG. 4 shows the mean ammonia and nitrite concentrations over the testperiod for the four mixtures along with the controls. For the BC5mixture, ammonia reached 0 mg/L on day 8 for the aquaria dosed with 100ml of BC5 mixture and day 10 for the aquaria dosed with 30 ml of BC5mixture. The ammonia concentration in the control aquaria did not reach0 mg/L until day 12. The highest mean ammonia concentration reached forthe control aquaria was 4.9 mg/L. However, for aquaria dosed with 30 mlof the BC5 bacterial mixture, the highest mean ammonia concentration was4.1 mg/L, while in the aquaria dosed with 100 ml of the BC5 bacterialmixture, the highest mean ammonia concentration was 2.4 mg/L. Thus, theaddition of the BC5 bacterial mixture to newly set-up aquaria resultedin less ammonia exposure to the fish.

The ammonia exposure curve area values for the aquaria dosed with 30 mlor 100 ml of the BC5 mixture were 67% and 37% of the control aquariacurve area value, respectively (Table 16); 1.5 and 2.7 times lessexposure to ammonia, respectively, for fish in the treatment aquaria.

TABLE 16 Toxicity Exposure Data for Bacterial Additives VI test. AmmoniaNitrite Exposure Exposure Treatment Value % of Control Area TreatmentValue % of Control Area Rtr7-100 5.7 17% 5.34 Rtr4-100 60.9 2% 1.99Rtr3-100 3.9 26% 7.87 Rtr7-100 25.5 4% 4.75 Rtr7-30 3.6 28% 8.59 Rtr4-3020.2 5% 6.01 BC5-100 2.7 37% 11.34 Rtr7-30 9.7 10% 12.45 Rtr4-100 2.738% 11.47 Rtr3-100 8.8 11% 13.81 Rtr4-30 2.2 45% 13.70 Rtr3-30 3.6 28%33.73 Rtr3-30 2.2 45% 13.71 BC5-100 3.1 33% 39.37 BC5-30 1.5 67% 20.38BC5-30 1.3 75% 90.56 Control 1.0 100% 30.56 Control 1.0 100% 121.13

Nitrite concentrations reached 0 mg/L by day 18 in aquaria dosed with100 ml of BC5 mixture, by day 21 in aquaria dosed with 30 ml of BC5mixture, and by day 23 in control aquaria. The control aquaria reached amean maximum nitrite control of 13.4 mg/L, while aquaria dosed with 30ml of the BC5 mixture had a mean maximum nitrite concentration of 8.9mg/L and those dosed with 100 ml of BC5 mixture had a maximum nitriteconcentration of only 4.5 mg/L (Table 15; FIG. 4).

The nitrite exposure curve area values for the aquaria dosed with 30 mlor 100 ml of the BC5 mixture were 75% and 33% of the control aquariacurve area value, respectively (Table 16); 1.3 and 3.1 times lessexposure to nitrite, respectively, for fish in the treatment aquaria.

Aquaria including bacterial mixture Rtr3, which had been stored for 118days, established nitrification faster than did control aquaria. Themean maximum ammonia concentration for the aquaria dosed with 30 ml or100 ml of the Rtr3 mixture was 3.1 and 1.9 mg/L, respectively (Table15). In contrast, the control aquaria demonstrated a mean maximumammonia concentration of 4.9 mg/L. The control aquaria reached a 0 mg/Lammonia concentration after 12 days, while the aquaria dosed with 30 mlor 100 ml of the Rtr3 bacterial mixture took only 9 and 7 days to reach0 mg/L, respectively (Table 15).

The mean maximum nitrite concentration was 13.4 mg/L in the controlaquaria, while the mean maximum nitrite concentration in aquaria dosedwith 30 ml or 100 ml of the Rtr3 bacterial mixture was only 5.9 mg/L and3.4 mg/L, respectively. The control aquaria reached a 0 mg/L nitriteconcentration in 23 days, while the aquaria dosed with 30 ml or 100 mlof Rtr3 bacterial mixture reach 0 mg/L after only 15 and 11 days,respectively (Table 15).

The ammonia exposure curve area values for the aquaria dosed with 30 mlor 100 ml of the Rtr3 mixture were 45% and 26% of the control aquariacurve area value, respectively (Table 15); 2.2 and 3.9 times lessexposure to ammonia, respectively, for fish in the treatment aquaria.

The nitrite exposure curve area values for the aquaria dosed with 30 mlor 100 ml of the Rtr3 mixture were 28% and 11% of the control aquariacurve area value, respectively (Table 15); 3.6 and 8.8 times lessexposure to nitrite, respectively, for fish in the treatment aquaria.

For the aquaria dosed with the Rtr4 mixture, the mean maximum ammoniaconcentration was 2.9 mg/L and 2.7 mg/L, respectively, for a dosagevolume of 30 ml and 100 ml (Table 15), while control aquaria reached amean maximum ammonia concentration of 4.9 mg/L. The ammonia exposurecurve area values for the aquaria dosed with 30 ml or 100 ml of the Rtr4mixture were 45% and 38% of the control aquaria curve area value,respectively. These values show that the addition of the mixtureresulted in 2.2 and 2.7 times less exposure to ammonia, respectively,for the fish in the treatment aquaria when compared to the controlaquaria (Table 15). Aquaria dosed with 30 ml of the Rtr4 mixturecompleted the nitrification cycle in 10 days, while nitrification wasestablished in 8 days for aquaria dosed 100 ml of the Rtr4 mixture(Table 15). Nitrification was established in 23 days in the controlaquaria.

The mean maximum nitrite concentration for the aquaria dosed with 30 mlor 100 ml of the Rtr4 bacterial mixture was 2.1 mg/L and 0.6 mg/L,respectively. The control aquaria had a mean maximum nitriteconcentration of 13.4 mg/L.

The nitrite exposure curve area values for the aquaria dosed with 30 mlor 100 ml of the Rtr4 mixture were 5% and 2% of the control aquariacurve area value, respectively; 20.2 and 60.9 times less exposure tonitrite, respectively, for fish in treatment aquaria (FIG. 4; Table 15).

The bacterial mixture Rtr7, which was a subculture from the BC5 mixture,demonstrated a significantly faster establishment of nitrification whencompared to the control aquaria. The control aquaria took 12 days toreach a 0 mg/L ammonia concentration, while aquaria dosed with 30 ml or100 ml of the Rtr7 bacterial mixture took only 7 and 6 days,respectively (Table 15). The mean maximum ammonia concentration foraquaria dosed with 30 ml or 100 ml of the R7 mixture was 1.9 mg/L and1.1 mg/L, respectively. This is in contrast to the control aquaria thathad a mean maximum ammonia concentration of 4.9 mg/L (Table 15).

The nitrite concentration reached a mean maximum concentration of 13.4mg/L in the control aquaria, while in aquaria dosed with 30 ml or 100 mlof the Rtr7 bacterial mixture the mean maximum nitrite concentration wasonly 3.7 mg/L and 1.4 mg/L, respectively (Table 15). Control aquariareached a 0 mg/L nitrite concentration in 23 days, while aquaria dosedwith 30 ml or 100 ml took only 10 and 7 days, respectively, to reach 0mg/L (Table 15; FIG. 4).

The ammonia exposure curve area values for aquaria dosed with 30 ml or100 ml of the Rtr7 mixture were 28% and 17% of the control aquaria curvearea value, respectively (Table 15); 3.6 and 5.7 times less exposure toammonia, respectively, for fish in the treatment aquaria.

The nitrite exposure curve area values for aquaria dosed with 30 ml or100 ml of the Rtr7 mixture were 10% and 4% of the control aquaria curvearea value, respectively; 5.7 and 25.5 times less exposure to nitrite,respectively, for fish in the treatment aquaria (Table 15).

In summary, the data from the test show that the various bacterialmixtures of the present invention accelerate the establishment ofnitrification in aquaria. Use of these mixtures in aquaria significantlyreduced the degree of ammonia and nitrite exposure to fish. The resultsfurther demonstrate that a mixture can be viably maintained over a longperiod of time (e.g., BC5), that the mixture can be stored for severalmonths (e.g., Rtr 3 and Rtr 4) and that successive generations of themixture retain their nitrifying ability (e.g., Rtr 7).

Example 13 Bacterial Additive Test VII

The goal of this test was to evaluate two mixtures of bacterial stainsof the present invention as they may be implemented in a “real world”setting while comparing their performance to that of commercialbacterial mixtures.

In general, a new aquarium owner first purchases the necessary equipmentfor setting-up an aquarium able to maintain aquatic life. The equipmentmay include the aquarium itself, decorations, a heater and filter, and awater conditioner. The aquarium is then assembled and filled with water,the filters are started, the heater is adjusted to the proper watertemperature and the water conditioner added to remove chlorine. At thispoint, the fish are usually added, but there may be insufficientpopulations of ammonia- and nitrite-oxidizing bacteria present tomaintain the ammonia and nitrite concentrations in the aquarium atbiologically safe (i.e., non-toxic) concentrations (e.g., below 0.5mg/L-N). Therefore, the newly set-up aquarium will exhibit what iscommonly referred to as “new tank syndrome” (i.e., elevatedconcentrations of ammonia and nitrite in the first several weeks aftersetting-up a new aquarium when an insufficient population of nitrifyingbacteria are present to maintain safe ammonia and nitriteconcentrations).

To at least partially alleviate new tank syndrome, a bottled mixture ofmicroorganisms or an enzyme mix (i.e., the bacterial mixture) may bepurchased and introduced to the new aquarium to accelerate, or in somecases, eliminate new tank syndrome. In theory, introduction of thebottled mixture should result in comparatively lower ammonia and nitriteconcentrations in an aquarium during its initial weeks than in theabsence of such a mixture. Also, less time should be required for theammonia and nitrite concentrations to reach 0 mg/L.

Thirty-three ten-gallon aquaria and thirty-three Penguin 170B(Marineland Aquarium Products) hang-on-the-back style power filters weresterilized, thoroughly rinsed and allowed to air dry. Each aquarium wasfilled with 10 lbs. of rinsed aquarium gravel (RMC Lonestar #3) and thefilter set-up on the back. Next, each aquarium was filled with 35 L ofcity water, which had been pre-filtered through activated carbon, andthe water level marked on each aquarium. This mark was used as a guideto indicate when aquaria water needed to be topped-off to account forwater lost due to evaporation or sampling. Deionized water was used fortopping-off the aquaria. The filters were allowed to run overnight priorto the addition of bacterial additives and fish.

On the first day of the test, the aquaria were topped off with deionizedwater to account for water and a baseline water sample. Carboncartridges (Marineland Aquarium Products, Part No. PA 0133) were rinsedwith tap water and placed in each filter. New BIOWHEELS (MarinelandAquarium Products, Part No. PR 1935B) were placed in each filter. Afterthirty minutes each tank was dosed with its designated bacterialadditive. The dosages were as described in Table 17. Thirty minutesafter the bacterial additives were added, a second set of water sampleswere extracted for analysis. Six assorted barbs [(Puntius conchonius)Rosy Barbs; (Puntius tetrazona) Albino Tiger Barbs and Tiger Barbs] werethen added to each tank. The fish in each aquarium were fed twice a day(at about 9:00 a.m. and again at 4:30 p.m.) with a total of 0.4 grams oftropical fish flakes per day.

Water samples were collected and analyzed tested daily for pH, ammonia,nitrite and conductivity. On Monday, Wednesday and Friday the water wastested for nitrate and turbidity. Anions and cations were measuredperiodically. Measurements for pH were made with a Denver InstrumentsModel 225 pH/Ion meter equipped with a Denver Instruments pH combinationelectrode. A Tecator FIAstar 5010 Analyzer was used to measure ammonia,nitrite and nitrate (as nitrogen) using methods described in TecatorApplication Notes. Cations (sodium, ammonium-nitrogen, potassium,magnesium and calcium) were analyzed using a Dionex DX500 System with aCS15 4-mm Analytical Column. Specific conductance was measured directlyin each tank at approximately 12:30 p.m. daily using a YSI Model 30hand-held salinity, conductivity and temperature system. Turbidity datawas determined with a DRT-100 turbidity meter (HF Scientific).

Two formulations containing bacterial strains of the present inventionwere tested along with four commercially available bacterial mixtures.On the first day of the test, 100 ml of the first formulation (Rtr5) wasadded to each of four aquaria, and 100 ml of the second formulation(Rtr7) was added to another four aquaria.

The commercially available bacterial mixtures were dosed according tomanufacturer's instructions, for the treatments of BIOZYME, CYCLE,FRITZ-ZYME NO.7 and STRESS ZYME. Furthermore, each of these commerciallyavailable bacterial mixtures was also tested at three times therecommended dosing level (Table 17). There were four replicate aquariaper treatment/dosage combination for a total of 33 aquaria (i.e.,(((4×3)×2)+(2×3)+3)=33).

The ammonia and nitrite trends for the treatments and control forBacterial Additives Test VII are shown in FIG. 5. For clarity ofpresentation, each of the commercially available bacterial mixturestested is presented with the control and the two test mixturescontaining the bacterial strain of the present invention. The scale ofeach plot is the same so comparisons between all the treatments can beeasily made. The data show that the Rtr5 and Rtr7 mixtures, containingthe bacterial stains of the present invention, significantly decreasedthe time necessary to establish nitrification in newly set-up aquariacompared to aquaria that were not dosed (i.e., the controls) or whichreceived a commercially available bacterial mixture. Furthermore, themaximum ammonia and nitrite concentrations reached in the aquaria whichwere dosed with either the Rtr5 or the Rtr7 bacterial mixture weresignificantly lower than all other treatments (FIG. 5; Table 18).

TABLE 18 Results of Bacterial Additives Test VII Time to ≦0.50 MeanMaximum Bacterial mg/L (days) Conc. (mg/L-N) Mixture Ammonia NitriteAmmonia Nitrite Rtr7 6 8 2.8 1.3 Rtr5 8 10 1.5 0.9 FRITZ-ZYME (3×) 10 248.5 3.1 FRITZ-ZYME 11 22 7.2 3.1 CYCLE (3×) 11 22 8.4 4.5 STRESS ZYME 1222 8.3 4.1 STRESS ZYME 12 25 8.6 4.3 (3×) BIOZYME 14 25 8.6 5.1 BIOZYME(3×) 15 30+ 8.8 6.5 CYCLE 15 30 8.8 4.3 Control 15 30 8.9 7.2

The Rtr5 and Rtr7 mixtures established nitrification in newly set-upaquaria significantly faster than the commercial mixtures and untreatedaquaria. Complete nitrification was established in 8 days with the Rtr7mixture and in 10 days with the Rtr5 mixture (Table 18). The closesttreatments to these were FRITZ-ZYME at the its normal dosing level,CYCLE at three times its normal dosing level, and STRESS ZYME at itsnormal dosage level; each of which took 22 days (Table 18). The Rtr5 andRtr7 mixtures were therefore 2.2 to 2.8 times faster at establishingnitrification then these other mixtures.

The difference in the maximum concentration of ammonia or nitritereached for the various mixtures and control were also significantlydifferent (Table 18). The mean (N=3) maximum ammonia concentration of1.5 mg/L reached during the test for the Rtr5 mixture was 4.8 times lessthan the FRITZ-ZYME (mean 7.2 mg/L, N=3), dosed at its normal level,which was the nearest commercially available mixture (Table 18). Themean maximum nitrite concentration for the Rtr5 mixture was 0.9 mg/L.Again, FRITZ-ZYME dosed at its normal level was the closest commerciallyavailable mixture with a mean maximum nitrite concentration of 3.1 mg/L.Therefore, the Rtr5 mixture was 3.4 times more effective at establishingnitrification then the presently available commercial mixtures tested.

The Rtr7 mixture exhibited the same trend as the Rtr5 mixture in thataquaria dosed with this mixture exhibited significantly lower maximumammonia-nitrogen and nitrite-nitrogen concentrations than aquaria dosedwith commercially available bacterial mixtures (Table 18). The Rtr7mixture had mean maximum ammonia and nitrite concentrations of 2.8 mg/Land 1.3 mg/L, respectively. These were 2.6 and 2.4 times lower,respectively, than the closest commercially available bacterial mixture(FRITZ-ZYME, dosed at its normal level) (FIG. 5; Table 18).

In terms of the exposure curves, the bacterial mixtures Rtr5 and Rtr7,which incorporate bacterial strains of the present invention,significantly outperformed the commercially available mixtures (Table19). In particular, Rtr7 performed better than any mixture with the fishexposed to just 13% of the ammonia and 5% of the nitrite of the control.Rtr5 was almost as effective, with ammonia exposure at 14% of controllevels and nitrite exposure at 9% of the control (Table 19). Theseresults mean that fish in aquaria receiving either Rtr7 or Rtr5 areexposed to 7.3 to 7.6 times less ammonia and 11.6 to 19.6 times lessnitrite than fish in control aquaria. After Rtr7 and Rtr5, the next bestmixtures reduced the exposure of ammonia and nitrite by only 50% whencompared to controls (Table 19).

TABLE 19 Toxicity exposure data for the Bacterial Additives VII test.Ammonia Nitrite Exposure Exposure Treatment Value % of control AreaTreatment Value % of control Area Rtr7 7.6 13% 5.90 Rtr7 19.6 5% 8.16Rtr5 7.3 14% 6.11 Rtr5 11.6 9% 13.85 Fritz 3x 2.6 39% 17.52 Fritz 1x 1.952% 82.71 Fritx 1x 2.5 40% 17.84 Stress 1x 1.8 55% 88.08 Stress 3x 1.952% 23.50 Cycle 3x 1.6 63% 100.05 Stress 1x 1.9 53% 23.76 Stress 3x 1.375% 119.42 Cycle 3x 1.7 59% 26.36 Fritz 3x 1.2 84% 134.60 Cycle 1x 1.376% 34.03 Bio 1x 1.1 88% 141.50 Bio 1x 1.3 79% 35.29 Control 1.0 100%159.97 Control 1.0 100% 44.82 Cycle 1x 1.0 104% 166.83 Bio 3x 0.9 111%49.90 Bio 3x 0.9 114% 182.30

Example 14 Bacterial Additive Test VIII

The goal of this test was to evaluate various mixtures of AOB strains ofthe present invention as they may be implemented in a “real world”setting. The performance of these mixtures of the present invention werecompared to other AOB strains of the present invention, as well as tocommercially available bacterial mixtures that claim they are suitablefor use in either freshwater or saltwater aquaria.

For this test, fifteen 10-gallon aquaria and fifteen Penguin 170B(Marineland Aquarium Products) hang-on-the-back style power filters weresterilized, thoroughly rinsed and allowed to air dry. On the followingday each tank was filled with 10 lbs. of rinsed Tideline Crushed Coral#5 and equipped with a sterilized power filter (PF 0170B) and rinsedcarbon cartridge. Each tank was filled with 35 L of artificial seawater.The seawater was a combination of Tropic Marine salt mix and post GACwater to a salinity of 30 ppt. The filters were allowed to run overnightprior to the addition of bacterial additives and fish.

The next morning the tanks were topped off with ultrapure water tocompensate for evaporation and water samples taken. Each tank was dosedwith one bacterial treatment, however no bacterial mixture was added tothe control group.

There were four treatments for this test: Reactor 3 included strains ofAOB of the present invention represented by SEQ ID NO:1, SEQ ID NO:2,and SEQ ID NO:3; Reactor 29 included strains of AOB of the presentinvention represented by SEQ ID NO:18, SEQ ID NO:19 and sequences fromtwo halophila-like strains; CYCLE (a commercially available bacterialmixture for use in freshwater or saltwater); and STRESS ZYME (anothercommercially available bacterial mixture for use in freshwater orsaltwater). Each treatment had three replicates. Aquaria receiving theReactor 3 and Reactor 29 treatments were dosed with 100 ml of eithermixture one time on the first day of the test. Aquaria receiving theCYCLE or STRESS ZYME treatments were dosed with 10 ml of eithertreatment on the first day of the test, an additional 10 ml on day 7 ofthe test and an additional 5 ml every 7 days after that for the durationof the test. Four assorted damsels (Pomacentrus spp.) were added to eachtank on the first day of the test and fed twice a day.

Water samples were collected and analyzed daily for pH, ammonia, nitriteand conductivity. On Monday, Wednesday and Friday the water was testedfor nitrate and turbidity. Measurements for pH were made with a DenverInstruments Model 225 pH/Ion meter equipped with a Denver Instruments pHcombination electrode. A Tecator FIAstar 5010 Analyzer was used tomeasure ammonia, nitrite and nitrate (as nitrogen) using methodsdescribed in Tecator Application Notes. Salinity was measured directlyin each tank daily using a YSI Model 30 hand-held salinity, conductivityand temperature system. Turbidity data was determined with a DRT-100turbidity meter (HF Scientific).

The mean ammonia concentrations for the four treatments and control aredepicted in FIG. 8. Treatment Reactor 29, which consisted of strains ofAOB represented by SEQ ID NO:18, SEQ ID NO:19 and two N. halophila-likestrains, oxidized ammonia markedly quicker than the other treatments.The mean maximum ammonia concentration of treatment Reactor 29 was alsosignificantly lower than the other three treatments. In fact, theammonia trend for the other three treatments over the first 14 days ofnewly set up aquaria were not significantly different than the control(non-inoculated) treatment. There was no evidence that adding more ofthe commercial AOB mixtures to the aquaria reduced the amount of timenecessary to establish ammonia oxidation.

These results demonstrate several points: (1) the strains of AOB of thepresent invention represented by SEQ ID NO:1, SEQ ID NO:2, and SEQ IDNO:3 are different than the bacterial strains of the present inventionrepresented by SEQ ID NO:18 and SEQ ID NO:19; (2) the AOB contained inthe commercially available mixtures (reported to be Nitrosomonaseuropaea) are not effective at controlling ammonia during the start-upof new seawater aquaria; and (3) that the AOB represented by SEQ IDNO:18 and SEQ ID NO:19 are effective at controlling and maintainingammonia concentrations in newly set-up seawater aquaria.

Example 15 Bacterial Additive Test IX

The goal of this test was to compare the biomass material from reactorSB7 (which contained AOB strains of the present invention represented bySEQ ID NO:18, SEQ ID NO:19 and two halophila-like strains) to aquariathat did not receive a bacterial inoculation.

For this test, eight 10-gallon aquaria and eight Penguin 170B(Marineland Aquarium Products) hang-on-the-back style power filters weresterilized, thoroughly rinsed and allowed to air dry. On the followingday each tank was filled with 10 lbs. of rinsed Tideline Crushed Coral#5 and equipped with a sterilized power filter (PF 0170B) and rinsedcarbon cartridge. Each tank was filled with 35L of artificial seawater.Artificial seawater was made by adding INSTANT OCEAN SeaSalts (AquariumSystems, Mentor, Ohio) to carbon filtered city water until the salinitywas 30 ppt. The aquaria were filled with the seawater and the filterswere allowed to run overnight prior to the addition of bacterialadditives and fish.

The next morning the tanks were topped off with ultrapure water tocompensate for evaporation and water samples taken. Then four tanks weredosed with 150 ml of SB7 reactor bacterial mixture. The other four tankswere not dosed with a bacterial mixture. The SB7 AOB reactor mixtureconsisted of strains of AOB of the present invention represented by SEQID NO:18, SEQ ID NO:19 and two N. halophila-like strains. Six clownfish(Amphiprion ocellaris) were added to each tank on the first day of thetest and fed twice a day. The fish feed was a mixture of frozen brineshrimp and Spirulina fish flakes. On Day 3 of the test, four additionalclownfish (Amphiprion ocellaris) were added to each aquarium.

Water samples were collected and analyzed tested daily for pH, ammonia,nitrite and conductivity. On Monday, Wednesday and Friday the water wastested for nitrate and turbidity. Measurements for pH were made with aDenver Instruments Model 225 pH/Ion meter equipped with a DenverInstruments pH combination electrode. A Tecator FIAstar 5010 Analyzerwas used to measure ammonia, nitrite and nitrate (as nitrogen) usingmethods described in Tecator Application Notes. Salinity was measureddirectly in each tank daily using a YSI Model 30 hand-held salinity,conductivity and temperature system. Turbidity data was determined witha DRT-100 turbidity meter (HF Scientific).

The mean ammonia concentrations for the SB7 treatment and control arepresented in FIG. 9. SB7 treatment including strains of AOB of thepresent invention represented by SEQ ID NO:18, SEQ ID NO:19 and two N.halophila-like strains oxidized ammonia markedly quicker than did thecontrol. The mean ammonia concentration reached 0 mg/L on day 9 in tanksreceiving the SB7 treatment, while 17 days elapsed in the controlaquaria before ammonia values reached the same level of 0 mg/L.Furthermore, the mean maximum ammonia concentration of the SB7 treatment(about 0.4 mg/L-N) was significantly lower than the control treatment(1.72 mg/L-N).

The results demonstrate that the strains of AOB of the present inventionrepresented by SEQ ID NO:18 and SEQ ID NO:19 are effective atcontrolling ammonia concentrations in newly set-up seawater aquaria.

Example 16 Bacterial Additive Test X

The goal of this test was to compare the biomass material from reactorSB7 (which contained AOB strains of the present invention represented bySEQ ID NO:18, SEQ ID NO:19 and two N. halophila-like strains) andreactor B7 (which contained two N. halophila-like AOB strains) toaquaria that received no bacterial inoculation.

For this test, twelve 10-gallon aquaria and twelve Penguin 170B(Marineland Aquarium Products) hang-on-the-back style power filters weresterilized, thoroughly rinsed and allowed to air dry. On the followingday each tank was equipped with a sterilized power filter (PF 0170B) andrinsed carbon cartridge. Each tank was filled with 19 L of artificialseawater. Artificial seawater was made by adding INSTANT OCEAN SeaSalts(Aquarium Systems, Mentor, Ohio) to carbon filtered city water until thesalinity was 29 ppt. The aquaria were filled with the seawater and thefilters were allowed to run overnight prior to the addition of bacterialadditives and ammonia.

The next morning the tanks were topped off with ultrapure water tocompensate for evaporation and water samples taken. Each treatment andthe control aquaria had four replicates. Four aquaria were dosed with150 ml of SB7 reactor bacterial mixture, four aquaria were dosed with150 ml of B7 reactor bacterial mixture, and four aquaria were not dosedwith any bacterial mixture. The SB7 AOB reactor mixture consisted ofstrains of AOB of the present invention represented by SEQ ID NO:18, SEQID NO:19 and two N. halophila-like strains. The B7 AOB reactor mixtureconsisted of two N. halophila-like strains of AOB.

Each day 11.5 mg of ammonia-nitrogen was added to each aquarium. Watersamples were collected and analyzed tested daily for pH, ammonia,nitrite and conductivity. On Monday, Wednesday and Friday the water wastested for nitrate and turbidity. Measurements for pH were made with aDenver Instruments Model 225 pH/Ion meter equipped with a DenverInstruments pH combination electrode. A Tecator FIAstar 5010 Analyzerwas used to measure ammonia, nitrite and nitrate (as nitrogen) usingmethods described in Tecator Application Notes. Salinity was measureddirectly in each tank daily using a YSI Model 30 hand-held salinity,conductivity and temperature system. Turbidity data was determined witha DRT-100 turbidity meter (HF Scientific).

The mean ammonia concentrations for the two treatments and control aredepicted in FIG. 10. The ammonia values for the aquaria that receivedeither reactor B7 or reactor SB7 treatment oxidized ammonia at nearlythe same rate; markedly faster than the control. The mean ammoniaconcentration reached 0 mg/L on day 3 for the tanks receiving either theB7 or SB7 treatments, and the mean maximum ammonia concentration of theB7 and SB7 treatment (about 0.2 mg/L-N) was significantly lower than thecontrol treatment (2.0 mg/L-N) (FIG. 9).

The results demonstrate that the strains of AOB of the present inventionrepresented by SEQ ID NO:18 and SEQ ID NO:19 are effective atcontrolling ammonia concentrations in newly set-up seawater aquaria.

While the description above refers to particular embodiments of thepresent invention, it should be readily apparent to people of ordinaryskill in the art that a number of modifications may be made withoutdeparting from the spirit thereof. The accompanying claims are intendedto cover such modifications as would fall within the true spirit andscope of the invention. The presently disclosed embodiments are,therefore, to be considered in all respects as illustrative and notrestrictive, the scope of the invention being indicated by the appendedclaims rather than the foregoing description. All changes that comewithin the meaning of and range of equivalency of the claims areintended to be embraced therein.

1. A composition comprising an isolated bacterial strain that oxidizesammonia to nitrite, wherein said bacterial strain comprises thenucleotide sequence set forth in SEQ ID NO:18.
 2. The composition ofclaim 1 wherein the composition is in a form selected from the groupconsisting of liquid, frozen, freeze-dried and powdered.
 3. Thecomposition of claim 1, wherein the composition is included in apolymer.
 4. The composition of claim 3, wherein the polymer is selectedfrom the group consisting of acrylamide, alginate, carrageenan, andcombinations thereof.
 5. A composition comprising a concentratedbacterial strain that oxidizes ammonia to nitrite, wherein the 16S rDNAof the bacterial strain has a nucleotide sequence that has at least 96%identity over the full length thereof to SEQ ID NO:18, whereinhybridization of the 16S rDNA occurs under the following stringentconditions: hybridization in 20% to 30% formamide, 0.9 M NaCl, 0.01%sodium dodecyl sulphate, 20 mM Tris/HCl pH 7.4 at 46° C., and washingwith 120 mM to 215 mM NaCl, 5 mM EDTA, 0.01% sodium dodecyl sulphate,and 20 mM Tris/HCl at 48° C.
 6. The composition of claim 5 wherein saidbacterial strain has a 16S rDNA sequence which is identical to SEQ IDNO:18.
 7. The composition of claim 5, further comprising a microorganismselected from the group consisting of ammonia-oxidizing microorganisms,nitrite-oxidizing microorganisms, nitrate-reducing microorganisms,heterotrophic microorganisms, and combinations thereof.
 8. An isolatednucleic acid consisting of: a nucleotide sequence that has at least 96%identity over the full length thereof to SEQ ID NO:18, whereinhybridization to SEQ ID NO:18 occurs under the following stringentconditions: hybridization in 30% formamide, 0.9 M NaCl, 0.01% sodiumdodecyl sulphate, 20 mM Tris/HCl pH 7.4 at 46° C., and washing with 120mM NaCl, 5 mM EDTA, 0.01% sodium dodecyl sulphate, and 20 mM Tris/HCl at48° C.
 9. The isolated nucleic acid of claim 8 wherein said sequence isidentical to SEQ ID NO:18.
 10. A composition comprising a bacterialstrain that oxidizes ammonia to nitrite including the nucleotidesequence as set forth in SEQ ID NO:18 and at least one other bacterialstrain that oxidizes ammonia to nitrite, wherein the at least one otherbacterial strain has 16S rDNA including a nucleotide sequenceindependently selected from the group consisting of: a nucleotidesequence that has greater than 98% identity over the full length thereofto SEQ ID NO:3, a nucleotide sequence that has greater than 98% identityover the full length thereof to SEQ ID NO:4, a nucleotide sequence thathas at least 96% identity over the full length thereof to SEQ ID NO:1, anucleotide sequence that has at least 96% identity over the full lengththereof to SEQ ID NO:2, a nucleotide sequence that has at least 96%identity over the full length thereof to SEQ ID NO:19 and a nucleotidesequence that has at least 96% identity over the full length thereof toSEQ ID NO:20, wherein hybridization of the 16S rDNA occurs under thefollowing stringent conditions: hybridization in 20% to 30% formamide,0.9 M NaCl, 0.01% sodium dodecyl sulphate, 20 mM Tris/HCl pH 7.4 at 46°C., and washing with 120 mM to 215 mM NaCl, 5 mM EDTA 0.01% sodiumdodecyl sulphate, and 20 mM Tris/HCl at 48° C.
 11. The composition ofclaim 10, said composition comprising a bacterial strain with a 16S rDNAincluding the nucleotide sequence as set forth in SEQ ID NO:1, abacterial strain with a 16S rDNA including the nucleotide sequence asset forth in SEQ ID NO:2, a bacterial strain with a 16S rDNA iucludingthe nucleotide sequence as set forth in SEQ ID NO:3, a bacterial strainwith a 16S rDNA including the nucleotide sequence as set forth in SEQ IDNO:4, a bacterial strain with a 16S rDNA including the nucleotidesequence as set forth in SEQ ID NO:18, a bacterial strain with a 16SrDNA including the nucleotide sequence as set forth in SEQ ID NO:19 anda bacterial strain with a 16S rDNA including the nucleotide sequence asset forth in SEQ ID NO:20.
 12. A composition comprising a bacterialstrain that oxidizes ammonia to nitrite including the nucleotidesequence as set forth in SEQ ID NO:18 and at least one other bacterialstrain that oxidizes ammonia to nitrite, wherein the at least one otherbacterial strain has 16S rDNA including a nucleotide sequenceindependently selected from the group consisting of: the nucleotidesequence as set forth in SEQ ID NO:3, the nucleotide sequence as setforth in SEQ ID NO:4, the nucleotide sequence as set forth in SEQ IDNO:1, the nucleotide sequence as set forth in SEQ ID NO:2, thenucleotide sequence as set forth in SEQ ID NO:19 and the nucleotidesequence as set forth in SEQ ID NO:20.